My Lords, back in the middle of the last century when I was Minister of State for Home Affairs in the old parliament in Northern Ireland, I had the task of reforming the local government system in Northern Ireland, which was then first past the post. This meant that in the west all the councillors were Irish nationalists and in the east all the councillors were Ulster unionists. Against some opposition from my own party, I introduced a Bill that included STV for local government. This resulted in the unionists in the west, who are the 40% minority, having representation for the first time, and they have it still today. Likewise, the Irish nationalists gained seats in the east that they would not have had under first past the post. So there was fair representation of Catholics and Irish nationalists in the eastern part of Northern Ireland and fair representation of unionists and protestants in the western part.
When it comes to UK elections, of course we still have first past the post because that is the UK law. What does that result in? It results in Sinn Féin/IRA winning many seats where they get less than 50% of the votes cast in their constituencies, and the result of that election is that they boycott the House of Commons. If we had STV or some other kind of proportional representation system in UK elections in Northern Ireland, I think we would have very few Sinn Féin MPs in the House of Commons.