He refused to take his seat in the House of Commons of the United Kingdom in line with the abstentionist policy of Sinn Féin. In the Northern Ireland Assembly, he served as the Minister for Regional Development in the Northern Ireland Executive from 8 May 2007 until 16 May 2011. While on a tour of UK party conferences in autumn 2005, he became the first Irish republican to address the Conservative Party conference and caused controversy by refusing to express regret over the Brighton hotel bombing.