Brian Kerr, Baron Kerr of Tonaghmore

In 1993, Kerr was appointed a Judge of the High Court and knighted, and in 2004 was appointed Lord Chief Justice of Northern Ireland,[2][3] only the second Roman Catholic to hold the position,[4] and sworn of the Privy Council.[5]

Kerr regarded the introduction in 1971 of internment without trial in Northern Ireland as having been "calamitous for the rule of law". However, he assessed his Troubles-era experience of the non-jury Diplock courts, introduced to prevent intimidation by paramilitaries, as broadly positive. Citing the "distinguished civil libertarian", Sir Louis Blom-Cooper, he proposed that the non-jury system (in which there was an automatic right of appeal) "was in some senses superior to the jury trial."[6]

As was usual for the Lord Chief Justice of Northern Ireland,[7] he succeeded Lord Carswell as the Northern Irish Lord of Appeal in Ordinary upon the latter's retirement.[3]

On 29 June 2009, he was created Baron Kerr of Tonaghmore, of Tonaghmore in the County of Down, and was introduced to the House of Lords the same day. He was the last person to be appointed a Lord of Appeal in Ordinary (and therefore the last to be given a life peerage under the Appellate Jurisdiction Act 1876). On 1 October 2009 he became one of the inaugural Justices of the new Supreme Court of the United Kingdom. He was the youngest member, at age 61.[8] He was succeeded as Lord Chief Justice of Northern Ireland on 3 July 2009 by Sir Declan Morgan.[9]

Lord Kerr of Tonaghmore dissented from the controversial judgment of the Supreme Court in R v Gnango, in which the court held that a person could be an accessory to his own murder.[10]

In the 2016 Article 50 "Brexit", and 2019 prorogation of Parliament, cases before the Supreme Court, Lord Kerr was a "close questioner of the government submissions".[11]

Asked to specify which had been his most important case, Kerr opted for the 2018 legal challenge to Northern Ireland abortion law brought by the Northern Ireland Human Rights Commission. The law prohibited abortion, even in cases of rape, incest and fatal foetal abnormality, and four of the seven justices, including Lord Kerr, ruled that this made the law in Northern Ireland incompatible with human rights legislation. "One only has to read the dreadful circumstances of the young women who were courageous enough to give … an account of their experiences in order to be struck how dreadful those experiences were... It was an extremely important case and one which I was very pleased to be part of."[6]

In 2014, Ulster University awarded Lord Kerr an honorary doctorate in law.[12]

In August 2020 it was announced that he would retire on 30 September 2020.[13]