The House of Commons disallows its MPs to also be members of foreign legislatures except for Commonwealth countries and, since 2000, Ireland. Why is Ireland a special case here?

The House of Commons Disqualification Act 1957 had disqualified from membership of the House of Commons those who were Members of non-Commonwealth legislatures. This clause was repeated in the House of Commons Disqualification Act 1975. This in turn was amended in 2000 to permit members of the Houses of the Oireachtas in the Republic of Ireland to sit in the House of Commons.

House of Commons Briefing Paper Number 06395, 11 September 2019: “Resignation from the House of Commons” § 4.5 “Dual Mandate Holders”.

A footnote points out that dual membership was also permissible before 1957.

The same document has another instance where Ireland is a special case: a criminal conviction with a prison sentence in Ireland also disqualifies members.

  • 2
    Regarding the footnote you point to, It's worth noting that from the Commonwealth's point of view, the Republic of Ireland only ceased to be a member in 1949.
    – origimbo
    Commented Jul 6, 2022 at 17:49
  • 3
    2000 is right after the Belfast Agreement, so I imagine it's related to that. Commented Jul 6, 2022 at 18:57
  • 7
    It's also worth noting that Ireland's relationship to the UK is closer than that of the commonwealth in many important respects; for example, Irish citizens are entitled to reside and work in the UK without any formalities.
    – phoog
    Commented Jul 6, 2022 at 19:39
  • It's probably because Irish Republicans (especially Sinn Fein members) have in the past stood for both parliaments, and the UK wished to extend that benefit to them after the Good Friday agreement. I don't have any evidence for this though.
    – Stuart F
    Commented Jul 7, 2022 at 18:56

1 Answer 1


It is a consequence of the special relationship between the UK and Ireland. And more generally the relationship between the UK and the Commonwealth (the countries that were formally in the British Empire)

Ireland was, until 1922, part of the UK. There was no sovereign Irish Parliament, Ireland was represented in the House of Commons by Irish MPs.

As part of the independence agreement, many of the rights that Irish people had were preserved. Irish people could move to the UK, vote, and stand for Parliament. (And by the principle of reciprocity, UK citizens could do the same). This means that UK and Irish citizens have the right to be both MPs and members of the Dáil.

Previously all Commonwealth had the same right to be MPs, but the conflict of interest led to the disqualification act.

The specific context is the Good Friday agreement. Sinn Fein does not recognise the right of the UK to any part of the island of Ireland. It contests elections both in the Republic of Ireland and in The North of Ireland. There was a specific desire by Sinn Fein that being elected to Parliament (in elections that they see as invalid) should not disqualify them from standing for the Dáil, and the principle of reciprocity applies here too. Hence the demand that the Parliament should allow people to be in both Houses.

This doesn't apply to the Commonwealth countries, as the situation of Northern Ireland is unique.

  • Formally or formerly? (...though some commonwealth countries were/are neither)
    – phoog
    Commented Jun 12, 2023 at 20:30
  • "many of the rights that Irish people had were preserved": which part of the agreement grants any of these rights to Irish citizens?
    – phoog
    Commented Jun 12, 2023 at 20:37
  • It grants them to British subjects who, (by happening to live on one side of a border) became Irish citizens.
    – James K
    Commented Jun 12, 2023 at 20:54
  • Which text has that effect? I'm asking because you don't seem to have read the document. At least, you are describing its effect in a way that is not consistent with the text of the document itself. Maybe you got that information from a secondary source, but you haven't said where it comes from, so I can only guess.
    – phoog
    Commented Jun 12, 2023 at 21:56

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