The Northern Assembly was one of the more controversial elements in the Stormont talks, and the basic structure of the new body was only agreed in the early hours of Good Friday morning as a light snowfall covered the ground outside.

The body will have 108 members, elected by proportional representation from the North's 18 constituencies. It will take over legislative and executive authority for the six existing government departments in Northern Ireland - Finance and Personnel, Agriculture, Economic Development, Education, Environment, Health and Social Security - and there is scope for taking on other matters as well.

The Assembly will be unlike most other parliaments in the democratic world which are based on the principle of majority rule. Because Northern Ireland is a divided society, safeguards have been built into the Belfast Agreement to ensure that all sections of the community can participate and work together successfully.

Ministerial positions and the chairs and composition of committees will be allocated in proportion to party strengths. In addition, the Assembly cannot take any action which infringes the European Convention on Human Rights or any future Bill of Rights in the North.

When they take their seats, members will have to adopt one of three designations: unionist, nationalist or other. When key decisions are being made, the motion must have cross-community support.

That is likely to mean, in the first instance, that a majority of members present and voting, including a majority of the unionist and nationalist designations, must support the measure. This is known as "parallel consent".

However, if parallel consent cannot be achieved, there is a fall-back position whereby a key decision can be taken with the support of a "weighted majority" of 60 per cent, including at least 40 per cent of nationalists and 40 per cent of unionists.

The agreement specifies the following as key decisions: election of the chair or speaker of the Assembly; election of the first minister and deputy first minister of the new administration; the standing orders by which the Assembly will operate; and budget allocations.

There is a potentially vital provision whereby, in other cases, a key decision can be triggered by a "petition of concern" from a significant minority of the membership, a minimum of 30 members. From the viewpoint of the anti-agreement parties, the DUP and the UK Unionists, it is crucial to win at least 30 seats in the Assembly or, if not, to have sufficient anti-agreement allies among the UUP group.

This would enable them to conduct procedural warfare, but to block key decisions they would need at least 60 per cent of the members who have designated themselves unionist.

After the elections on June 25th, it is thought the first meeting of the new body may take place in early July. The Northern Ireland Office would only say "as soon as practicable".

No decision has been taken as to where the Assembly will meet: nationalists are unenthusiastic about the old Stormont parliament, and it is understood a number of other locations in the Belfast area have been examined. Nor are there any official details of salaries and expenses, although there has been speculation about £30,000 a year plus an additional £30,000 for secretarial assistance and other expenses.

At its first meeting, the chair and deputy chair of the Assembly will be elected, on a cross-community basis. There will be committees to monitor all the departments controlled by the Assembly. The agreement allows for up to 10 departments, with ministers to run them.

It is likely also that the first minister and deputy first minister of the new administration will be elected at the Assembly's first meeting or shortly after that. Since these are "key decisions", the successful candidates will have to be voted in on a cross-community basis. In a normal democracy, the first minister would, as the equivalent of a prime minister, have the power to nominate his or her cabinet. But under the terms of the agreement, these posts will be filled in proportion to party strengths in the Assembly.

The first minister and deputy first minister are expected to be David Trimble and John Hume respectively, and their duties will include co-ordinating the work of the cabinet or "executive committee".

The executive committee will seek to agree a programme of government on a yearly basis, incorporating an agreed budget and subject to approval by the Assembly.

A party may decline to nominate a person to serve as minister, and there is clearly a difficulty for an anti-agreement party - assuming it wanted to claim a position to which it was entitled - because of the role some ministers at least will have to play on the North-South ministerial council.

Ministers will be required to pledge, among other things, their "commitment to non-violence and exclusively peaceful and democratic means". A minister may be removed from office by a cross-community vote of no confidence, and one can envisage a situation where, for example, some unionist members would seek to have a Sinn Fein minister removed in the event of a renewal of IRA violence.

The Secretary of State will continue to have responsibility for Northern Ireland Office matters that have not been devolved to the Assembly, for example, security and prisons.

There will be a transitional period between the election of the Assembly next month and the formal transfer of powers early next year, following the passage of legislation at Westminster.

Thus the Assembly will be without legislative or executive powers for approximately the first seven months of its existence. Despite this "shadow" existence, the Assembly will nevertheless be charged with making preparations for the effective functioning of the North-South ministerial council and its associated implementation bodies as well as the British-Irish council, representing the two governments and the devolved institutions in Northern Ireland, Scotland and Wales.

The North-South council is to be made up of ministers from both sides of the Border working together on matters of mutual interest. The council is based on the European model, and different ministers will attend at different times, depending on the topic. Ministers will require the approval of the Assembly and the Oireachtas, respectively, for decisions which go beyond their "defined authority".

In addition to the first meeting of the Assembly, inaugural meetings of the North-South council and the British-Irish council must take place "as soon as practically possible" after the June 25th poll. The agreement specifies that all three bodies "will meet regularly and frequently" before the formal transfer of powers.

Most important of all, the agreement lays down that representatives of the "Northern Ireland transitional administration" and Dublin will, in co-operation with the British government, agree by October 31st on at least 12 areas for North-South co-operation, including at least six requiring the establishment of new cross-Border or all-island implementation bodies.

The British and Irish governments will then "as an absolute commitment" make the necessary legislative and other arrangements to ensure these implementation bodies are functioning at the time of the formal transfer of powers to the Assembly, which will take over legislative authority for the new bodies "as soon as possible thereafter".

The bottom line, spelt out in the agreement, is: no North-South council, no Assembly. The two bodies are "mutually interdependent" and "one cannot successfully function without the other". But any further development of the North-South arrangements must be by agreement and with the "specific endorsement" of the Assembly and the Oireachtas.

Will Sinn Fein be able to take up ministerial posts in view of the fact that the IRA has not decommissioned? Participants in the agreement promised "to use any influence they may have, to achieve the decommissioning of all paramilitary arms within two years".

To shore up unionist support during the referendum campaign the British Prime Minister, Mr Blair, pledged that legislation setting up the Assembly would ensure that those associated with violence would not be allowed to become ministers.

However, it is difficult to see how he could ensure the exclusion of Sinn Fein, in response to unionist pressure, without breaching the agreement.

The duties of the first minister and deputy first minister will include co-ordinating the work of the cabinet or "executive committee".