Alexander Andrew Mackay Irvine, Lord Irvine of Lairg, QC, PC (born June 23, 1940), known as Derry Irvine, is a British lawyer and political figure who served as Lord Chancellor under his former pupil Tony Blair.

Born in Inverness, he studied law at the University of Glasgow and Christ's College, Cambridge. He taught law at the London School of Economics and was called to the bar in 1967. In 1970 he fought Hendon North as a Labour Party candidate. He became a QC in 1978 and head of chambers in 1981. Among his pupil barristers were Tony Blair and Cherie Booth, and at their wedding he dubbed himself "Cupid QC" for having introduced them. During the 1980s he also became a Recorder, and then a Deputy High Court Judge.

He was a legal adviser to the Labour Party through the 1980s, which included advice on how to expel members of the Militant Tendency, and he was given a Life Peerage in 1987. His appointment as Lord Chancellor after Blair's election victory in 1997 was widely expected after he had served for five years as Shadow Lord Chancellor. The highlight of his period in office was the incorporation of the European Convention on Human Rights into United Kingdom law. Irvine devised a measure to maintain the supremacy of Parliament while allowing Judges to declare Acts of Parliament not to be in compliance with the Convention.

In addition to his traditional role of supervising the legal system, in 2001 he gained responsibility for a wide range of constitutional issues including human rights and freedom of information. This was interpreted as a move away from a strong freedom of information law, as Irvine was thought not to be a firm believer in the concept.

Irvine's reputation derives from his skills as a lawyer rather than those as a politician, and he occasionally faced controversy as Lord Chancellor. Soon after his appointment, the Lord Chancellor's official residence in the Palace of Westminster was redecorated at a cost to the taxpayer of over half a million pounds (the hand-printed wallpaper accounted for £59,000). Although the decision had been taken by an all-party House of Lords Committee before the election, much of the criticism devolved on him.

Early in 2003 he was awarded a pay rise of £22,691 as a result of a formula designed to keep his salary ahead of that of the Lord Chief Justice. After an outcry he accepted a more modest rise.

His resignation was announced in June 2003, with his successor Lord Falconer of Thoroton. At the same time it was announced that the post of Lord Chancellor would be abolished, made certain by the Constitutional Reform Act 2005. Irvine was known to be against such a policy and it was widely speculated that his departure had not been voluntary.