According to Sinn Fein, a party associated with an illegal organisation holding illegal weapons, the United Kingdom government acted unlawfully in suspending devolution in Northern Ireland. This legal hare was set running by a London political scientist, Brendan O'Leary, in The Irish Times on February 5th. The proper legal view, I submit, using United Kingdom, international and Irish constitutional law, is that London acted perfectly legally. It is, in contrast, the Irish Government which may be at risk of breaching the Belfast Agreement.

First, United Kingdom law. Northern Ireland, in municipal law, has been an integral part of the United Kingdom for almost 200 years. Parliamentary sovereignty remains an important domestic legal doctrine. London devolved power to Belfast in 1920; it took it back in 1972; it did the same thing again in 1973 and 1974.

The Northern Ireland Act, 1998, empowered the Assembly, and provided variously for other institutions (all of which went live on December 2nd, 1999). The Northern Ireland Act, 2000, empowered the Secretary of State to suspend (not collapse) these provisions (section 5 referring to a new international agreement dealing with the North-South implementation bodies).

The first constitutional act implemented much of the Belfast Agreement, signed by the two governments on April 10th, 1998. The suspension act, unquestionably legal in United Kingdom law (since it is not contrary to European law), did not breach that important international agreement.

A great deal has been made of the repeal of section 75 of the Government of Ireland Act, 1920 (particularly by Geraldine Kennedy on February 14th and 15th). This has not altered United Kingdom (or international) law one iota, as can be seen from: paragraph 33 of Strand One of the Belfast Agreement; section 5(6) of the Northern Ireland Act, 1998; and paragraph 13 of the memorandum of understanding, dealing with devolution, presented to parliament by the Lord Chancellor in October 1999.

The Irish Government was locked out of Strand One of the multi-party negotiations at Castle Buildings in 1996-98. There is no way, under the Belfast Agreement, it subsequently became jointly responsible for devolution in Northern Ireland, with or without suspension.

There is a considerable irony here. The Irish Government's code of omerta over the Boland case in Dublin in 1974 contributed to the end of the Sunningdale power-sharing experiment. If London allows legal untruths about Section 75 and repeal to continue to circulate (without clarification), it will lose a great deal more than one case in Belfast in 2000.

Second, international law. There is no express provision for suspension of institutions in the Belfast Agreement (the idea came from London and Dublin in July 1999 as an alternative to exclusion), but that does not make it unlawful in international and/or domestic law.

The UK never undertook to put Northern Ireland under permanent joint authority. The second paragraph 4 of Strand Three states: "There will be no derogation from the sovereignty of either government (sic)." Nor did the two states agree to exclude suspension of the Belfast Agreement itself.

The Belfast Agreement, however, does contain extensive provisions for review, only some of which - and arguably not the Assembly reviewing Sinn Fein ministers continuing without decommissioning - involve the participation of the Irish Government. A review, under Section 2(3) of the suspension act, is now a condition for the restoration of the institutions. Dublin, having failed to prevent suspension, will, by fighting review, make that more unlikely.

Paragraph 5 of the Declaration of Support and paragraph 13 of Strand Two contain an important principle of the Belfast Agreement, interlinkage (which stemmed from the conduct of the multi-party negotiations. This was included as a preamble in the international agreement of March 8th, 1999, which established the North-South bodies.

When Westminster was legislating the (aborted) suspension failsafe last July, a draft international agreement was made available to MPs. This envisaged putting the implementation bodies on a care-and-maintenance basis, and recovering their functions after four months, essentially dissolution. (The British-Irish Agreement Act, 1999, and Article 29.7.2 of the Constitution were not then apparently problematic for Dublin.)

It is clear, from a comment of Lord Falconer in the House of Lords on February 9th, that the United Kingdom still holds to this view; the assent of Dublin is necessary to help suspend only the implementation bodies. It emerged only on Sunday, February 13th, that the Irish Government had refused to do what it seemed to have considered possible and desirable in July 1999.

This failure to help the United Kingdom government (a tactic to prevent suspension?) is arguably a breach of the Belfast Agreement. The Irish Government's only possible defence, that suspension by the United Kingdom was a material breach, only entitles the Irish State to terminate or suspend the Belfast Agreement.

Practically, under paragraph 11 of Strand Two, the implementation bodies are dependent upon the North-South Ministerial Council, which has been effectively suspended. If the Irish Government should seek administratively to keep the bodies alive, London can always, in the continuing absence of an agreement, counter this with similar measures.

The Taoiseach sought to justify his Government's inaction on suspension by pleading the Irish Constitution, in spite of the principle that a state party may not invoke the provisions of its internal law as justification for its failure to perform a treaty.

Third, Irish law. There is a strange idea that the Belfast Agreement was incorporated into Bunreacht na hEireann, through Article 29.7.1 on May 22nd, 1998 (Geraldine Kennedy arguing at the time that the United Kingdom's role in Northern Ireland was thereby circumscribed).

This is not the case for the following reasons:

One: the issue was originally ratification (as can be seen from paragraph 2 of the Validation, Implementation and Review section), Dublin being concerned about a Crotty-type challenge over the implementation bodies alienating the powers of government.

Two: the Irish State consented to be bound by the bilateral Belfast Agreement when Bertie Ahern signed on April 10th, 1998. It could not have unbound itself in international law, even if the people had voted against the Belfast Agreement (article 29.7.1 was a dead letter from the first in Irish law).

Three: Dail Eireann, and the Referendum Commission, referred to the amendment of Article 29 of Bunreacht na hEireann only, not to incorporating, or even approving (as happened in Northern Ireland), the Belfast Agreement.

Four: while Article 46 may not prohibit such constitutional incorporation, Article 29.5-6 on treaty-making powers might well do so. Incorporation of the Belfast Agreement (if true) could be a very bad precedent for the Irish State's conduct of foreign policy; the courts have generally held the issue to be non-justiciable.

Sinn Fein threatening legal action is not the worst that can happen. The party would get short shrift in Belfast, since the court would look simply at the Northern Ireland Act, 2000. No doubt the argument in Dublin would be more complicated (one awaits the opinion of the Attorney General, Michael McDowell SC).

The new distinguished Supreme Court, however, would have no difficulty disentangling its constitutional law from international law and the municipal law of another state.

Austen Morgan is a barrister practising in London and author of a forthcoming book on the Belfast Agreement