A huge credibility battle has erupted between Sinn Féin and the British and Irish governments after the Independent Monitoring Commission (IMC) said some Sinn Féin leaders were involved in authorising the alleged IRA robbery of the Northern Bank.
The Sinn Féin president, Mr Gerry Adams, described the IMC report as "rubbish" and challenged the Taoiseach, Mr Ahern, to arrest him.
However, the Irish Government-appointed member of the four-man body, Mr Joe Brosnan, a former senior civil servant, said it would be a resigning matter for him if the allegations ultimately proved to be unfounded.
The monitoring body yesterday supported the Taoiseach's allegation that senior Sinn Féin politicians had advance knowledge of the £26.5 million robbery of the Northern Bank, which the IMC blamed on the IRA.
It went further by stating that Sinn Féin members allegedly in the IRA leadership sanctioned the Northern Bank and three other major robberies last year in Belfast and Strabane.
"In our view Sinn Féin must bear its share of responsibility for all the incidents. Some of its senior members, who are also senior members of PIRA, were involved in sanctioning the series of robberies," it said.
The fourth IMC report, published yesterday, set the scene for a huge confrontation, with the Sinn Féin leadership denying IRA involvement in the bank robbery and any Sinn Féin foreknowledge of the raid.
The IMC did not specify which Sinn Féin leaders they alleged were involved in sanctioning the robbery.
In Dublin, neither would the Minister for Justice, Mr McDowell, name names, but said the Sinn Féin politicians allegedly implicated were household names regularly seen on television.
Mr Adams interpreted the allegations as being directed at him and Sinn Féin's chief negotiator, Mr Martin McGuinness. "What I think the Taoiseach has to do and what the Minister for Justice has to do is to face up to the import of their remarks, have us arrested, bring us forward into the due process," he said in Dublin yesterday evening.
He said the report made "unsubstantiated" allegations.
Mr Adams, however, said he could not sue.
"My solicitor has told me," he told reporters yesterday, "that in terms of the libel laws, the likes of me cannot actually claim to be libelled by being accused of being a member of the IRA, given that to be libelled means that your peer group will be embarrassed and find in some way that they couldn't deal with you."
The DUP deputy leader, Mr Peter Robinson, uncharacteristically agreed with Mr Adams by demanding that the PSNI Chief Constable, Mr Hugh Orde, arrest the Sinn Féin president and other party leaders.
The IMC members trenchantly stood over their allegations. Mr John Grieve, former deputy commissioner of the London Metropolitan Police, emphatically rejected republican denials of IRA involvement in the robbery.
"Quite frankly, my position is that the people who have denied it on behalf of the Provisional IRA have got some brass neck," he said.
The IMC recommended that financial penalties be imposed against Sinn Féin, which could take the form of cutting Assembly allowances or pay. Since April last year, £120,000 in Assembly allowances were withheld from Sinn Féin as a result of an alleged IRA assault against Mr Bobby Tohill in Belfast last spring.