The handover of the IRA's guns and explosives would be scheduled to begin in September, with regular reports coming from the arms decommissioning body, headed by General John de Chastelain, to chart progress or otherwise.

Loyalist terror groups who have called a ceasefire would be expected to disarm at the same time.

They have said they would not start the process before the IRA makes the first move.

For the IRA, that would leave eight months for the handing over or supervised destruction of tonnes of weapons, from basic revolvers and pistols to at least one SAM-7 ground-to-air missile and Semtex plastic explosive.

The size of the IRA's arsenal can only be estimated.

The LVF is the only group to have handed in arms

Usually reliable security sources suggest it has about 650 assault rifles of various origin, but mostly Russian AK47s and American Armalites.

There is also thought to be about two tonnes of Semtex in secret storage dumps.

Most of this equipment is thought to have been secretly shipped to the IRA from Libya's Colonel Gaddafi in the 1970s and 1980s.

The IRA is also believed to have about 20 heavy calibre machineguns, at least a dozen general purpose machineguns, hundreds of revolvers and automatic pistols and about 40 rocket propelled grenade launchers.

About three-quarters of IRA weaponry is stored in the Irish Republic.

Between 1985 and 1993, the republic's police uncovered more than 800 guns and 300,000 bullets along with some bomb-making equipment.

But much of the IRA threat lies not only in its arms stockpiles, but also in its weapons-making capability.

Dissident threat

Many raids by the security forces north and south of the Irish border have uncovered not only explosives, but also complete engineering workshops where bombs, mortar launchers and other sophisticated weapons are built.

But any acceptance by the IRA to decommission would not remove the threat to peace posed by dissident republican and loyalist groupings.

The Real IRA is thought to have Semtex removed from Provisional IRA bunkers and also home-made mortars and grenade launchers, a small number of rifles, machineguns, pistols, handguns and detonators.

The Continuity IRA is believed to have a huge improvised grenade launcher, a small quantity of assault rifles, hand guns, grenades, Semtex and detonators.

The Irish National Liberation Army, the oldest republican splinter group, has dozens of rifles, machine pistols, handguns and an unknown quantity of commercial explosive.

Arms tactics

The Loyalist Volunteer Force is the only group so far to decommission weapons, in a gesture seen by some security sources as a move to secure early release for its prisoners.

A handful of weapons - some of them very old - were handed over for destruction.

It still has a small number of handguns, rifles, commercial explosive and detonators.

The Ulster Volunteer Force is believed to have hundreds of rifles and pistols, some home-made weapons and Powergel commercial explosive.