LONDON -- The arsenal lies buried in bunkers and includes plastic explosives, surface-to-air missiles, assault rifles and enough bullets, according to London's Observer newspaper, "to kill every man, woman and child" in Northern Ireland.
This is the Irish Republican Army's weapons hoard, the final hurdle that could still cause the collapse of the Northern Ireland peace process.
With Britain poised by tomorrow to impose direct rule over Northern Ireland if the IRA doesn't commit itself to giving up weapons, politicians are working overtime to try to prevent the entire peace deal from unraveling.
Two months after the province saw its local government restored and watched in wonder as Protestants and Roman Catholics worked side by side in a power-sharing assembly for the first time, Northern Ireland is again embroiled in crisis and brinkmanship.
The province's leading Protestant politician, David Trimble, has postdated a letter of resignation as Northern Ireland's first minister.
Gerry Adams, president of Sinn Fein, the IRA's political wing, has threatened to walk away from the peace process if the British government restores its rule over Northern Ireland.
This crisis is different from all the others that have been overcome during Northern Ireland's often fraught peace process because it involves the issues of life and death -- and the armaments of a guerrilla war: bullets, bombs and guns.
Many are blaming the IRA for the latest crisis. Politicians from across the spectrum demand that the group, which first called a cease-fire in 1994, answer two questions: Will it give up its arms? If so, when?
"This was always going to be the most difficult of issues of all to solve, the most difficult psychologically," says Martin McGuinness, Sinn Fein's chief negotiator and Northern Ireland's education minister.
The deadlock over IRA arms has been years in the making, pushed down the pipeline in a peace process that yielded the historic 1998 Good Friday accord, which appeared to end a terrorist war that left 3,600 dead since the 1960s. The arms issue is so emotional that the word disarmament isn't used. Instead, it's called decommissioning.
In the Good Friday document, parties agreed to "use any influence they may have to achieve the decommissioning of all paramilitary arms." The province's paramilitary groups were to give up their weapons by May 22 in a disarmament overseen by an international panel headed by Canadian Gen. John de Chastelain.
Except for a small cache handed over by a small group of Protestant paramilitaries, no weapons have been turned in. The latest report by the Canadian general was apparently so dire that it wasn't released publicly.
Eventually, the irresistible force of the peace process would have to meet the immovable object of IRA arms.
"The arms issue has to be sorted out or it will haunt us tomorrow, the next day and the next," says Alan McFarland, a Northern Ireland Assembly member for the Ulster Unionists, the province's major Protestant party.
What helped set the confrontation in motion was the deal in November to establish the local assembly. The Ulster Unionists went against their stated "no guns, no government" pledge by agreeing to enter the local assembly with Sinn Fein. But the Protestant party needed some assurances on weapons. The IRA agreed to appoint a representative to deal with the decommissioning body.
To get his bitterly split rank and file to agree to the local assembly, Ulster Unionist leader Trimble wrote his postdated letter of resignation as Northern Ireland's first minister.
He also scheduled a meeting for Saturday at which the party could again vote on its place in the local government and the executive Cabinet. Without any weapons turned in, it's doubtful the rank and file will agree to see its top politicians serve in the Cabinet.
In effect, Trimble forced everyone's hand, the British and Irish governments, and the IRA's.
Rather than see the peace process collapse, the British government pushed through legislation this week to freeze the local assembly and restore direct rule over Northern Ireland. The bill is to receive royal assent and become law tomorrow. Northern Ireland Secretary Peter Mandelson has expressed hope that he will not have to implement the legislation.
Even if the British government reasserts control over Northern Ireland, providing breathing space for the peace process, the IRA will still have to be dealt with.
It's difficult to get any answers on the hand-over of weapons from the 300 or so members believed to be combatants in a shadowy army that amassed many of its weapons by smuggling them in from Libya in the 1980s. Protestant paramilitary groups are also armed, but not as heavily as the IRA.
The province is also patrolled by Europe's most heavily armed police force, the Royal Ulster Constabulary, and by British troops.