River Thames

Image of the deity Æsus on the Gallo-Roman "Pillar of the Boatmen"

A statue of Old Father Thames by Raffaelle Monti at St John's Lock, Lechlade

According to Mallory and Adams, the Thames, from Middle English Temese, is derived from the Brittonic name for the river, Tamesas (from *tamēssa),[3] recorded in Latin as Tamesis and yielding modern Welsh Tafwys "Thames".

The name element Tam may have meant "dark" and can be compared to other cognates such as Russian темно (Proto-Slavic *tĭmĭnŭ), Lithuanian tamsi "dark", Latvian tumsa "darkness", Sanskrit tamas and Welsh tywyll "darkness" and Middle Irish teimen "dark grey".[3] [lower-alpha 2] The origin is shared by many other river names in Britain, such as the River Tamar at the border of Devon and Cornwall, several rivers named Tame in the Midlands and North Yorkshire, the Tavy on Dartmoor, the Team of the North East, the Teifi and Teme of Wales, the Teviot in the Scottish Borders and a Thames tributary the Thame.

Kenneth H. Jackson proposed that the name of the Thames is not Indo-European (and of unknown meaning),[5] while Peter Kitson suggested that it is Indo-European but originated before the Britons and has a name indicating "muddiness" from a root *tā-, 'melt'.[6]

Early variants of the name include:

• Tamesa (Brittonic)[4]
• Tamesis (Latin)[4]
• Tamis, Temes (Old English)[4]
• Tamise, Thamis (1220) (Middle English, Anglo-Norman French)[lower-alpha 3]

Indirect evidence for the antiquity of the name "Thames" is provided by a Roman potsherd found at Oxford, bearing the inscription Tamesubugus fecit (Tamesubugus made [this]). It is believed that Tamesubugus' name was derived from that of the river.[7] Tamese was referred to as a place, not a river in the Ravenna Cosmography (c. AD 700).

The river's name has always been pronounced with a simple t /t/; the Middle English spelling was typically Temese and the Brittonic form Tamesis. A similar spelling from 1210, "Tamisiam" (the accusative case of "Tamisia"; see Kingston upon Thames § Early history), is found in the Magna Carta.[8]

Sculpture of Tamesis. Downstream keystone of the central arch of Henley Bridge

The Thames through Oxford is sometimes called the Isis. Historically, and especially in Victorian times, gazetteers and cartographers insisted that the entire river was correctly named the Isis from its source down to Dorchester on Thames and that only from this point, where the river meets the Thame and becomes the "Thame-isis" (supposedly subsequently abbreviated to Thames) should it be so called. Ordnance Survey maps still label the Thames as "River Thames or Isis" down to Dorchester. Since the early 20th century this distinction has been lost in common usage outside of Oxford, and some historians suggest the name Isis is nothing more than a truncation of Tamesis, the Latin name for the Thames. Sculptures titled Tamesis and Isis by Anne Seymour Damer are located on the bridge at Henley-on-Thames, Oxfordshire (the original terracotta and plaster models were exhibited at the Royal Academy, London, in 1785. They are now on show at the River and Rowing Museum in Henley).[9]

Richard Coates suggests that while the river was as a whole called the Thames, part of it, where it was too wide to ford, was called *(p)lowonida. This gave the name to a settlement on its banks, which became known as Londinium, from the Indo-European roots *pleu- "flow" and *-nedi "river" meaning something like the flowing river or the wide flowing unfordable river.[10][11]

The river gives its name to three informal areas: the Thames Valley, a region of England around the river between Oxford and West London; the Thames Gateway; and the greatly overlapping Thames Estuary around the tidal Thames to the east of London and including the waterway itself. Thames Valley Police is a formal body that takes its name from the river, covering three counties. In non-administrative use, the river's name is used in those of Thames Valley University, Thames Water, Thames Television, publishing company Thames & Hudson, Thameslink (north–south rail service passing through central London) and South Thames College. An example of its use in the names of historic entities is the Thames Ironworks and Shipbuilding Company.

After the river took its present-day course, many of the banks of the Thames Estuary and the Thames Valley in London were partly covered in marshland, as was the adjoining Lower Lea Valley. Streams and rivers like the River Lea, Tyburn Brook and Bollo Brook drained into the river, while some islands, e.g. Thorney Island, formed over the ages. The northern tip of the ancient parish of Lambeth, for example, was marshland known as Lambeth Marshe, but it was drained in the 18th century; the street name Lower Marsh preserves a memory.[12]

Until the middle of the Victorian era malaria was commonplace beside the River Thames, even in London, and was frequently lethal. Some cases continued to occur into the early 20th century. Draining of the marshes had to do with its eradication, but the causes are complex and unclear.

The East End of London, also known simply as the East End, was the area of London east of the medieval walled City of London and north of the River Thames, although it is not defined by universally accepted formal boundaries; the River Lea can be considered another boundary.[13] Most of the local riverside was also marshland. The land was drained and became farmland; it was built on after the Industrial Revolution.

Canvey Island in southern Essex (area 18.45 km², 7.12 sq mi; population 40,000[14]) was once marshy, but is now a fully reclaimed island in the Thames estuary, separated from the mainland of south Essex by a network of creeks. Lying below sea level, it is prone to flooding at exceptional tides, but has nevertheless been inhabited since Roman times.

The sea level in the Thames estuary is rising and the rate of rise is increasing.[22][23]

Sediment cores up to 10 m deep collected by the British Geological Survey from the banks of the tidal River Thames contain geochemical information and fossils which provide a 10,000-year record of sea-level change.[24] Combined, this and other studies suggest that the Thames sea-level has risen more than 30 m during the Holocene at a rate of around 5–6 mm per year from 10,000 to 6,000 years ago.[24] The rise of sea level dramatically reduced when the ice melt nearly concluded over the past 4,000 years. Since the beginning of the 20th century, rates of sea level rise range from 1.22 mm per year to 2.14 mm per year.[24]

The Thames River Basin[25] District, including the Medway catchment, covers an area of 6,229 sq mi (16,130 km²).[26] The entire river basin is a mixture of urban and rural, with rural landscape predominating in the western part. The area is among the driest in the United Kingdom. Water resources consist of groundwater from aquifers and water taken from the Thames and its tributaries, much of it stored in large bank-side reservoirs.[26]

The Thames itself provides two-thirds of London's drinking water, while groundwater supplies about 40 per cent of public water supplies in the overall catchment area. Groundwater is an important water source, especially in the drier months, so maintaining its quality and quantity is extremely important. Groundwater is vulnerable to surface pollution, especially in highly urbanised areas.[26]

The Jubilee River at Slough Weir

St John's Lock, near Lechlade

The River Thames in Oxford

Brooks, canals and rivers, within an area of 3,842 sq mi (9,951 km²),[27] combine to form 38 main tributaries feeding the Thames between its source and Teddington Lock. This is the usual tidal limit; however, high spring tides can raise the head water level in the reach above Teddington and can occasionally reverse the river flow for a short time. In these circumstances, tidal effects can be observed upstream to the next lock beside Molesey weir,[27] which is visible from the towpath and bridge beside Hampton Court Palace. Before Teddington Lock was built in 1810–12, the river was tidal at peak spring tides as far as Staines upon Thames.

In descending order, non-related tributaries of the non-tidal Thames, with river status, are the Churn, Leach, Cole, Ray, Coln, Windrush, Evenlode, Cherwell, Ock, Thame, Pang, Kennet, Loddon, Colne, Wey and Mole. In addition, there are occasional backwaters and artificial cuts that form islands, distributaries (most numerous in the case of the Colne), and man-made distributaries such as the Longford River. Three canals intersect this stretch: the Oxford Canal, Kennet and Avon Canal and Wey Navigation.

Its longest artificial secondary channel (cut), the Jubilee River, was built between Maidenhead and Windsor for flood relief and completed in 2002.[28][29]

The non-tidal section of the river is managed by the Environment Agency, which is responsible for managing the flow of water to help prevent and mitigate flooding, and providing for navigation: the volume and speed of water downstream is managed by adjusting the sluices at each of the weirs and, at peak high water, levels are generally dissipated over preferred flood plains adjacent to the river. Occasionally, flooding of inhabited areas is unavoidable and the agency issues flood warnings. Due to stiff penalties applicable on the non-tidal river, which is a drinking water source before treatment, sanitary sewer overflow from the many sewage treatment plants covering the upper Thames basin should be rare in the non-tidal Thames. However, storm sewage overflows are still common in almost all the main tributaries of the Thames[30][31] despite claims by Thames Water to the contrary.[32]

London Stone at Staines, built in 1285 marked the customs limit of the Thames and the City of London's jurisdiction.

Waterstand of Thames at low tide (left) and high tide (right) in comparison at Blackfriars Bridge in London

Below Teddington Lock (about 55 mi or 89 km upstream of the Thames Estuary), the river is subject to tidal activity from the North Sea. Before the lock was installed, the river was tidal as far as Staines, about 16 mi (26 km) upstream.[33] London, capital of Roman Britain, was established on two hills, now known as Cornhill and Ludgate Hill. These provided a firm base for a trading centre at the lowest possible point on the Thames.[34]

A river crossing was built at the site of London Bridge. London Bridge is now used as the basis for published tide tables giving the times of high tide. High tide reaches Putney about 30 minutes later than London Bridge, and Teddington about an hour later. The tidal stretch of the river is known as "the Tideway". Tide tables are published by the Port of London Authority and are available online. Times of high and low tides are also posted on Twitter.

The principal tributaries of the River Thames on the Tideway include the rivers Crane, Brent, Wandle, Ravensbourne (the final part of which is called Deptford Creek), Lea (the final part of which is called Bow Creek), Roding (Barking Creek), Darent and Ingrebourne. In London, the water is slightly brackish with sea salt, being a mix of sea and fresh water.

The Thames Barrier provides protection against floods.

This part of the river is managed by the Port of London Authority. The flood threat here comes from high tides and strong winds from the North Sea, and the Thames Barrier was built in the 1980s to protect London from this risk.

The Nore is the sandbank that marks the mouth of the Thames Estuary, where the outflow from the Thames meets the North Sea. It is roughly halfway between Havengore Creek in Essex and Warden Point on the Isle of Sheppey in Kent. Until 1964 it marked the seaward limit of the Port of London Authority. As the sandbank was a major hazard for shipping coming in and out of London, in 1732 it received the world's first lightship. This became a major landmark, and was used as an assembly point for shipping. Today it is marked by Sea Reach No. 1 Buoy.[35]

London City Airport is on the site of a dock.

The River Thames contains over 80 islands ranging from the large estuarial marshlands of the Isle of Sheppey and Canvey Island to small tree-covered islets like Rose Isle in Oxfordshire and Headpile Eyot in Berkshire. They are found all the way from Fiddler's Island in Oxfordshire to the Isle of Sheppey in Kent. Some of the largest inland islands, for example Formosa Island near Cookham and Andersey Island at Abingdon, were created naturally when the course of the river divided into separate streams.

In the Oxford area the river splits into several streams across the floodplain (Seacourt Stream, Castle Mill Stream, Bulstake Stream and others), creating several islands (Fiddler's Island, Osney and others). Desborough Island, Ham Island at Old Windsor and Penton Hook Island were artificially created by lock cuts and navigation channels. Chiswick Eyot is a landmark on the Boat Race course, while Glover's Island forms the centre of a view from Richmond Hill.

Islands of historical interest include Magna Carta Island at Runnymede, Fry's Island at Reading, and Pharaoh's Island near Shepperton. In more recent times Platts Eyot at Hampton was the place where Motor Torpedo Boats (MTB)s were built, Tagg's Island near Molesey was associated with the impresario Fred Karno and Eel Pie Island at Twickenham was the birthplace of the South East's R&B music scene.

Westminster Abbey and the Palace of Westminster (commonly known today as the Houses of Parliament) were built on Thorney Island, which used to be an eyot.

About 450,000 years ago, in the most extreme Ice Age of the Pleistocene, the Anglian, the furthest southern extent of the ice sheet reached Hornchurch[38] in east London, the Vale of St Albans, and the Finchley Gap.

It dammed the river in Hertfordshire, resulting in the formation of large ice lakes, which eventually burst their banks and caused the river to divert onto its present course through the area of present-day London.

The ice lobe which stopped at present-day Finchley deposited about 14 metres of boulder clay there.[39] Its torrent of meltwater gushed through the Finchley Gap and south towards the new course of the Thames, and proceeded to carve out the Brent Valley in the process.[40]

The Anglian ice advance resulted in a new course for the Thames through Berkshire and on into London, after which the river rejoined its original course in southern Essex, near the present River Blackwater estuary. Here it entered a substantial freshwater lake in the southern North Sea basin, south of what is called Doggerland. The overspill of this lake caused the formation of the Channel River and later the Dover Strait gap between present-day Britain and France. Subsequent development led to the continuation of the course that the river follows at the present day.[41]

Most of the bedrock of the Vale of Aylesbury comprises clay and chalk that formed at the end of the ice age and at one time was under the Proto-Thames. At this time the vast underground reserves of water formed that make the water table higher than average in the Vale of Aylesbury.[42]

A geological map of the London Basin; the London Clay is marked in dark brown.

The confluence of the Rivers Thames and Brent. The narrowboat is heading up the River Brent. From this point as far as Hanwell the Brent has been canalised and shares its course with the main line of the Grand Union Canal. From Hanwell the Brent can be traced to various sources in the Barnet area.

At the height of the last ice age, around 20,000 BC, Britain was connected to mainland Europe by a large expanse of land known as Doggerland in the southern North Sea Basin. At this time, the Thames' course did not continue to Doggerland but flowed southwards from the eastern Essex coast where it met the waters of the proto-Rhine–Meuse–Scheldt delta[41] flowing from what are now the Netherlands and Belgium. These rivers formed a single river – the Channel River (Fleuve Manche) – that passed through the Dover Strait and drained into the Atlantic Ocean in the western English Channel.

Upon the valley sides of the Thames and some of its tributaries can be seen other terraces of brickearth, laid over and sometimes interlayered with the clays. These deposits were brought in by the winds during the periglacial periods, suggesting that wide, flat marshes were then part of the landscape, which the new rivers proceeded to cut into.

The steepness of some valley sides indicates very much lower mean sea levels caused by the glaciation locking up so much water upon the land masses, thus causing the river water to flow rapidly seaward and so erode its bed quickly downwards.

The original land surface was around 350 to 400 ft (110 to 120 m) above the current sea-level. The surface had sandy deposits from an ancient sea, laid over sedimentary clay (this is the blue London Clay). All the erosion down from this higher land surface, and the sorting action by these changes of water flow and direction, formed what is known as the Thames River Gravel Terraces.

Since Roman times and perhaps earlier, the isostatic rebound from the weight of previous ice sheets, and its interplay with the eustatic change in sea level, have resulted in the old valley of the River Brent, together with that of the Thames, silting up again. Thus, along much of the Brent's present-day course, one can make out the water-meadows of rich alluvium, which is augmented by frequent floods.

Some of the earliest written references to the Thames (Latin: Tamesis) occur in Julius Caesar's account of his second expedition to Britain in 54 BC,[52] when the Thames presented a major obstacle and he encountered the Iron Age Belgic tribes (Catuvellauni and Atrebates) along the river. At the confluence of the Thames and Cherwell was the site of early settlements and the River Cherwell marked the boundary between the Dobunni tribe to the west and the Catuvellauni to the east (these were pre-Roman Celtic tribes). In the late 1980s a large Romano-British settlement was excavated on the edge of the village of Ashton Keynes in Wiltshire.

Starting in AD 43, under the Emperor Claudius, the Romans occupied England and, recognising the river's strategic and economic importance, built fortifications along the Thames valley including a major camp at Dorchester. Cornhill and Ludgate Hill provided a defensible site near a point on the river both deep enough for the era's ships and narrow enough to be bridged; Londinium (London) grew up around the Walbrook on the north bank around the year 47. Boudica's Iceni razed the settlement in AD 60 or 61, but it was soon rebuilt; and once the bridge was built, it grew to become the provincial capital of the island.

The next Roman bridges upstream were at Staines on the Devil's Highway between Londinium and Calleva (Silchester). Boats could be swept up to it on the rising tide, with no need for wind or muscle power.

A Romano-British settlement grew up north of the confluence, partly because the site was naturally protected from attack on the east side by the River Cherwell and on the west by the River Thames. This settlement dominated the pottery trade in what is now central southern England, and pottery was distributed by boats on the Thames and its tributaries.

Competition for the use of the river created the centuries-old conflict between those who wanted to dam the river to build millraces and fish traps and those who wanted to travel and carry goods on it. Economic prosperity and the foundation of wealthy monasteries by the Anglo-Saxons attracted unwelcome visitors and by around AD 870 the Vikings were sweeping up the Thames on the tide and creating havoc as in their destruction of Chertsey Abbey.

A 1616 engraving by Claes Van Visscher showing the Old London Bridge, with St Mary's Overie (over-the-river), now Southwark Cathedral in the foreground

Once King William had won total control of the strategically important Thames Valley, he went on to invade the rest of England. He had many castles built, including those at Wallingford, Rochester, Windsor and most importantly the Tower of London. Many details of Thames activity are recorded in the Domesday Book. The following centuries saw the conflict between king and barons coming to a head in AD 1215 when King John was forced to sign the Magna Carta on an island in the Thames at Runnymede. Among a host of other things, this granted the barons the right of Navigation under Clause 23.

Another major consequence of John's reign was the completion of the multi-piered London Bridge, which acted as a barricade and barrage on the river, affecting the tidal flow upstream and increasing the likelihood of the river freezing over. In Tudor and Stuart times, various kings and queens built magnificent riverside palaces at Hampton Court, Kew, Richmond on Thames, Whitehall and Greenwich.

As early as the 1300s, the Thames was used to dispose of waste matter produced in the city of London, thus turning the river into an open sewer. In 1357, Edward III described the state of the river in a proclamation: "... dung and other filth had accumulated in divers places upon the banks of the river with ... fumes and other abominable stenches arising therefrom."[53]

The growth of the population of London greatly increased the amount of waste that entered the river, including human excrement, animal waste from slaughter houses, and waste from manufacturing processes. According to historian Peter Ackroyd, "a public lavatory on London Bridge showered its contents directly onto the river below, and latrines were built over all the tributaries that issued into the Thames."[53]

River Thames frost fair, circa 1685

During a series of cold winters the Thames froze over above London Bridge: in the first Frost Fair in 1607, a tent city was set up on the river, along with a number of amusements, including ice bowling.

In good conditions, barges travelled daily from Oxford to London carrying timber, wool, foodstuffs and livestock. The stone from the Cotswolds used to rebuild St Paul's Cathedral after the Great Fire in 1666 was brought all the way down from Radcot. The Thames provided the major route between the City of London and Westminster in the 16th and 17th centuries; the clannish guild of watermen ferried Londoners from landing to landing and tolerated no outside interference. In 1715, Thomas Doggett was so grateful to a local waterman for his efforts in ferrying him home, pulling against the tide, that he set up a rowing race for professional watermen known as "Doggett's Coat and Badge".

Michael Faraday giving his card to Father Thames, caricature commenting on a letter of Faraday's on the state of the river in The Times in July 1855

By the 18th century, the Thames was one of the world's busiest waterways, as London became the centre of the vast, mercantile British Empire, and progressively over the next century the docks expanded in the Isle of Dogs and beyond. Efforts were made to resolve the navigation conflicts upstream by building locks along the Thames. After temperatures began to rise again, starting in 1814, the river stopped freezing over.[54] The building of a new London Bridge in 1825, with fewer piers (pillars) than the old, allowed the river to flow more freely and prevented it from freezing over in cold winters.[55]

Throughout early modern history the population of London and its industries discarded their rubbish in the river.[56] This included the waste from slaughterhouses, fish markets, and tanneries. The buildup in household cesspools could sometimes overflow, especially when it rained, and was washed into London's streets and sewers which eventually led to the Thames.[57] In the late 18th and 19th centuries people known as mudlarks scavenged in the river mud for a meagre living.

Satirical cartoon by William Heath, showing a woman observing monsters in a drop of London water (at the time of the Commission on the London Water Supply report, 1828)

In the 19th century the quality of water in the Thames deteriorated further. The discharge of raw sewage into the Thames was formerly only common in the City of London, making its tideway a harbour for many harmful bacteria. Gasworks were built alongside the river, and their by-products leaked into the water, including spent lime, ammonia, cyanide, and carbolic acid. The river had an unnaturally warm temperature caused by chemical reactions in the water, which also removed the water's oxygen.[58] Four serious cholera outbreaks killed tens of thousands of people between 1832 and 1865. Historians have attributed Prince Albert's death in 1861 to typhoid that had spread in the river's dirty waters beside Windsor Castle.[59] Wells with water tables that mixed with tributaries (or the non-tidal Thames) faced such pollution with the widespread installation of the flush toilet in the 1850s.[59] In the 'Great Stink' of 1858, pollution in the river reached such an extreme that sittings of the House of Commons at Westminster had to be abandoned. Chlorine-soaked drapes were hung in the windows of Parliament in an attempt to stave off the smell of the river, but to no avail.[60]

There followed a concerted effort to contain the city's sewage by constructing massive sewer systems on the north and south river embankments, under the supervision of engineer Joseph Bazalgette. Meanwhile, there were similar huge projects to ensure the water supply: reservoirs and pumping stations were built on the river to the west of London, slowly helping the quality of water to improve.

The Victorian era was one of imaginative engineering. The coming of the railways added railway bridges to the earlier road bridges and also reduced commercial activity on the river. However, sporting and leisure use increased with the establishment of regattas such as Henley and the Boat Race. One of the worst river disasters in England was on 3 September 1878, when the crowded pleasure boat Princess Alice collided with the Bywell Castle, killing over 640 people.

The Thames as it flows through east London, with the Isle of Dogs in the centre

The growth of road transport, and the decline of the Empire in the years following 1914, reduced the economic prominence of the river. During the Second World War, the protection of certain Thames-side facilities, particularly docks and water treatment plants, was crucial to the munitions and water supply of the country. The river's defences included the Maunsell forts in the estuary, and the use of barrage balloons to counter German bombers using the reflectivity and shapes of the river to navigate during the Blitz.

In the post-war era, although the Port of London remains one of the UK's three main ports, most trade has moved downstream from central London. In the late 1950s, the discharge of methane gas in the depths of the river caused the water to bubble, and the toxins wore away at boats' propellers.[61]

The decline of heavy industry and tanneries, reduced use of oil-pollutants and improved sewage treatment have led to much better water quality compared to the late 19th and early- to mid-20th centuries and aquatic life has returned to its formerly 'dead' stretches.

Alongside the entire river runs the Thames Path, a National Route for walkers and cyclists.

In the early 1980s a pioneering flood control device, the Thames Barrier, was opened. It is closed to tides several times a year to prevent water damage to London's low-lying areas upstream (the 1928 Thames flood demonstrated the severity of this type of event).

A view of the Thames as it passes through London, composed of 29 photos taken from the ISS in 2021

In the late 1990s, the 7 mi (11 km) long Jubilee River was built as a wide "naturalistic" flood relief channel from Taplow to Eton to help reduce the flood risk in Maidenhead, Windsor and Eton,[62] although it appears to have increased flooding in the villages immediately downstream.

In 2010, the Thames won the largest environmental award in the world: the $350,000 International Riverprize.[63]

In August 2022, the first few miles of the river dried up due to the previous month's heatwave, and the source of the river temporarily moved five miles to beyond Somerford Keynes.[64]

Passenger service on the River Thames

In London there are many sightseeing tours in tourist boats, past riverside attractions such as the Houses of Parliament and the Tower of London. There are also regular riverboat services co-ordinated by London River Services. London City Airport is situated on the Thames, in East London. Previously it was a dock.

The leisure navigation and sporting activities on the river have given rise to a number of businesses including boatbuilding, marinas, ships chandlers and salvage services.

In summer, passenger services operate along the entire non-tidal river from Oxford to Teddington. The two largest operators are Salters Steamers and French Brothers. Salters operate services between Folly Bridge, Oxford and Staines. The whole journey takes four days and requires several changes of boat.[65] French Brothers operate passenger services between Maidenhead and Hampton Court.[66] Along the course of the river a number of smaller private companies also offer river trips at Oxford, Wallingford, Reading and Hampton Court.[67] Many companies also provide boat hire on the river.

The London Cable Car, over the River Thames

The London Cable Car over the Thames from the Greenwich Peninsula to the Royal Docks has been in operation since the 2012 Summer Olympics.

Metropolitan Marine Policing Unit patrol vessel, Nina Mackay III, on the Thames River in London

The river is policed by five police forces. The Thames Division is the River Police arm of London's Metropolitan Police, while Surrey Police, Thames Valley Police, Essex Police and Kent Police have responsibilities on their parts of the river outside the metropolitan area. There is also a London Fire Brigade fire boat on the river. The river claims a number of lives each year.[68]

As a result of the Marchioness disaster in 1989 when 51 people died, the Government asked the Maritime and Coastguard Agency, the Port of London Authority and the Royal National Lifeboat Institution (RNLI) to work together to set up a dedicated Search and Rescue service for the tidal River Thames. As a result, there are four lifeboat stations on the River Thames: at Teddington, Chiswick, Tower (based at Victoria Embankment/Waterloo Bridge) and Gravesend.[69]

Pool of London looking west, from the high-level walkway on Tower Bridge. Click on the picture for a longer description.

A container ship unloading at Northfleet Hope terminal, Tilbury

A ship heading downstream past Coryton Refinery

Rubbish traps are used on the Thames to filter debris as it flows through central London.

The Thames is maintained for navigation by powered craft from the estuary as far as Lechlade in Gloucestershire and for very small craft to Cricklade. The original towpath extends upstream from Putney Bridge as far as the connection with the now disused Thames and Severn Canal at Inglesham, one and a half miles upstream of the last boat lock near Lechlade. From Teddington Lock to the head of navigation, the navigation authority is the Environment Agency. Between the sea and Teddington Lock, the river forms part of the Port of London and navigation is administered by the Port of London Authority. Both the tidal river through London and the non-tidal river upstream are intensively used for leisure navigation.

The non-tidal River Thames is divided into reaches by the 45 locks. The locks are staffed for the greater part of the day, but can be operated by experienced users out of hours. This part of the Thames links to existing navigations at the River Wey Navigation, the River Kennet and the Oxford Canal. All craft using it must be licensed. The Environment Agency has patrol boats (named after tributaries of the Thames) and can enforce the limit strictly since river traffic usually has to pass through a lock at some stage. A speed limit of 8 km/h (4.3 kn) applies. There are pairs of transit markers at various points along the non-tidal river that can be used to check speed – a boat travelling legally taking a minute or more to pass between the two markers.

The tidal river is navigable to large ocean-going ships as far upstream as the Pool of London and London Bridge. Although London's upstream enclosed docks have closed and central London sees only the occasional visiting cruise ship or warship, the tidal river remains one of Britain's main ports. Around 60 active terminals cater for shipping of all types including ro-ro ferries, cruise liners and vessels carrying containers, vehicles, timber, grain, paper, crude oil, petroleum products, liquified petroleum gas etc.[70] There is a regular traffic of aggregate or refuse vessels, operating from wharves in the west of London. The tidal Thames links to the canal network at the River Lea Navigation, the Regent's Canal at Limehouse Basin and the Grand Union Canal at Brentford.

Upstream of Wandsworth Bridge a speed limit of 8 kn (15 km/h) is in force for powered craft to protect the riverbank environment and to provide safe conditions for rowers and other river users. There is no absolute speed limit on most of the Tideway downstream of Wandsworth Bridge, although boats are not allowed to create undue wash. Powered boats are limited to 12 knots between Lambeth Bridge and downstream of Tower Bridge, with some exceptions. Boats can be approved by the harbour master to travel at speeds of up to 30 knots from below Tower Bridge to past the Thames Barrier.[71]

The administrative powers of the Thames Conservancy to control river traffic and manage flows have been taken on with some modifications by the Environment Agency and, in respect of the Tideway part of the river, such powers are split between the agency and the Port of London Authority.