Jeremy Carver explains Clifford Chance's role in the Northern Ireland peace process advising UUP leader David Trimble

Since The Lawyer (21 April) revealed that I had advised David Trimble and the Ulster Unionist Party (UUP), on aspects of the Belfast Agreement of 10 April 1998, I have received varied responses.

Other lawyers express pleasure that a lawyer might have played a part in constructing peace - but are curious as to what in fact I could have done. Non-lawyers wonder how on earth a lawyer could contribute to what is a profoundly political and sectarian conflict.

It was as well that I did not ask that question when approached for advice towards the end of 1997. As the multi-party negotiations continued, one of the issues confronting David Trimble as leader of the UUP was the impact of the Irish constitution, in so far as it laid claim to the whole of Ireland as a single state. The question posed was whether it was possible to enter into an agreement affecting the future of Northern Ireland with a government which existed, constitutionally, on the basis that there was no separate Northern Ireland?

Article 2 of the 1937 Constitution defined as "national territory" the whole of Ireland. In the leading case of McGimpsey ([1988] IR567; [1990] IR110), the Supreme Court determined that Article 2, with other provisions of the constitution, amounted to a "claim of right", and was thus a "constitutional imperative". On this basis, no government in Dublin could, as a matter of Irish law, enter into any commitment which could not be presented as the pursuit of a united Ireland. Removal of this basic obstacle was thus a pre-condition to any meaningful progress in the multi-party talks.

I have advised different governments for more than 25 years. I could not have done so without appreciating the political cross currents which affect the legal issues.

Fortunately, Austen Morgan, a barrister with a knowledge of Irish affairs and the current situation, was retained with me. I was thus able to learn with a sympathetic guide, the character of the environment in which we needed to advise.

Even if it was not beyond the scope of this short article, it would be wrong to rehearse our analysis of those aspects of the Irish constitution which we felt needed to be reviewed if the talks were to succeed. We were helped enormously by the fact that the Constitution Review Group - an all-party group appointed by the Irish government - had published a detailed analysis in May 1996.

Confining ourselves to those aspects of the constitution which we felt constituted an obstacle to the talks, we devised alternative language which, we hoped, would both remove the problems and not be controversial in Dublin.

Our reflections on this issue were largely complete before Christmas. The multi-party talks had become sterile, but it was expected that the break might provide an opportunity for an initiative.

This arrived with the announcement on 12 January 1998 of new heads of agreement of the participants. This, effectively, foreclosed the opportunity to deal with the wider issues in respect of the constitution.

The two governments acknowledged the need for change to Articles 2 and 3, which were the core of the problem. Although our talks with senior officials and advisers to the Irish government produced a significant measure of agreement on many of the points we identified, it was these two articles alone which were addressed substantially in the Belfast Agreement.

The January heads of agreement had identified another area on which we felt we could help. It anticipated the establishment of a north-south ministerial council, to which matters of common concern could be referred. Alongside this body, other north-south bodies might be created to undertake the conduct of common functions. Very little detailed thought seemed to have been given in either capital as to how such bodies might be established. Suspicion of what was intended was thus inevitable in Northern Ireland.

One result of three and a half years of intensive litigation in London following the collapse of the International Tin Council in 1985 was that the true nature and characteristics of an international body were subject to a more intense legal scrutiny than ever previously undertaken. We were thus able to suggest not only how a body could be created so as to be independent of the two states creating it and of the various communities in which it would function - we could also advise how such bodies might be constituted within the domestic legal systems of both parts of Ireland.

The use of such bodies genuinely independent of either community might diffuse any sense of being ruled or controlled by north or south.

The company or corporation, constituted by agreement of natural persons with the object of acquiring legal capacity independent of its members, emerged slowly over the past few centuries.

International organisations composed of states - global or regional - have really only taken root since 1945. As the pace of international activity increases, so does the need for such bodies, tailored to meet the demands of complex communities. There is a lack of international law of general application to international organisations. Here, we felt, was an area where we might make a contribution.

The go-ahead to discuss these technical matters with Dublin came relatively late in the day. What was evident was not only a common concern to explore how such bodies might be organised - it was remarkable that there was no partisanship.

It was agreed from the start that our discussions were purely technical in nature. Neither we nor our counterparts had any instructions on political issues; and neither of us could in any way compromise our respective principals. Our discussions were frank and uncomplicated.

Late in March, we met in London for a day of talks with Dublin officials. It was plain that we had made progress throughout the day. I left the office late by car and, as I was driving down Whitehall listening to the news, I observed a group emerging from a gloomy Downing Street. At almost that moment, the BBC announced a crisis in the talks.

The Irish government had complained to Tony Blair at the absence of progress on the issue of north-south bodies. The sense of achievement arose subsequently. The agreement, when concluded in the following week, added new substance to what we had discussed. Perhaps our groundwork provided a foundation for that result.

The Belfast Agreement is a substantial achievement for the people of Northern Ireland. No-one pretends that it will provide a solution for all the problems.

There are still obstacles to be overcome, and opportunities to be seized. A great deal of detailed work is required to translate the agreement into the institutions on which the future can be built. It is the politicians - the representatives of the people - who must lead.

Lawyers can contribute to that process - as indeed to resolve any differences which must be governed by law.