Security sources candidly admit that - despite a huge intelligence effort - they remain alarmingly ignorant of the state of play at the highest levels of the IRA, and why it should have staged the pounds 26m Belfast bank robbery in December. "The list of theories is almost endless," said a senior source. Another added: "We're still searching around for the answer to the question of why they did it."
But the organisation is emitting unmistakeable signals of increasing restlessness and tensions in its ranks, and using language with an ever-greater edge of menace and implied threat. Although the security assessment is that the IRA is not intent on a return to full-scale conflict, a sense of worsening crisis and deepening deadlock has raised the possibility that events could spiral out of control.
The IRA warned: "Do not underestimate the seriousness of the situation," in an angry statement which appeared to be hastily released after an earlier statement failed, in republican eyes, to make the desired impact on London and Dublin.
A new round of verbal confrontation is expected next week when the Independent Monitoring Commission will again blame the IRA for the robbery and discuss sanctions against republicans.
Although Sinn Fein can be expected to make tactical use of this in the hope of cloaking the party in the status of victimhood, the resulting clashes are likely to worsen an already poisonous atmosphere.
The British and Irish governments are in close alignment in saying the IRA committed the Belfast robbery, in believing Sinn Fein leaders knew of it, and in blaming republicans for the present impasse. A central issue is that London and Dublin flatly reject repeated republican denials of involvement. They therefore regard each new denial from the Sinn Fein leaders, Gerry Adams and Martin McGuinness, as self-inflicted blows on their own credibility.
Republicans and the Irish government have been particularly at odds, with the Taoiseach, Bertie Ahern, listing IRA robberies and beatings, and glaring at Sinn Fein representatives in the Dail as he spoke of "the kind of tactics in which you and some of your friends engage".
The deterioration in relations between the republicans and the two governments has happened at a startling rate. Only a few months ago the IRA offered to put its entire armoury beyond use as part of an emerging political deal.
At that point the authorities were hopeful of a historic breakthrough which would see a new administration led by Sinn Fein and the Rev Ian Paisley's Democratic Unionist Party.
But now the IRA has been blamed for carrying out a robbery on a spectacular scale, which has caused many to question its intentions of ever giving up on illegal activity and moving into democratic politics.
The organisation has now said its arms offer is off the table, a tactic it has resorted to in the past and which has proved reversible. The sense of anger in republican ranks is now so strong, however, that this will not easily happen again.
Before devolution can be achieved, Ian Paisley, as well as the governments, will in any event require the most binding promises from republicans that bank robberies and other illegalities will never happen again.
The IRA is in no mood to offer such assurances but, even if it eventually did, this will inevitably be followed by a long period of verification that IRA illegality has ceased. This means the governments' goal of devolution is highly unlikely to be achieved until 2006 at the earliest, which in turn means a lengthy period of vacuum in which the peace process might unravel further.
At senior political and security levels there is a complete lack of certainty as to why republicans should have brought such disruption to a peace process which they value so much, and which has delivered them such political success.
"It was a Canary Wharf without the casualties, that's one theory," said one source, referring to the 1996 bombing in London which killed two people and inflicted huge damage. That attack was said by the organisation to be a response to the "bad faith" of the Major government.
Another theory is that "they did it because they could", trying to take advantage of the fact that previous smaller robberies have been played down in both London and Dublin.
Some senior people believe it resulted from what one described as "sheer arrogance".
It has not been ruled out that the purpose was to provide a "retirement fund" for IRA members who would become inactive. Another idea is that the IRA always needs large amounts of money and that this amount proved irresistible.
A related notion is that, since the bank was about to be taken over by another, this pushed the IRA into moving sooner rather than later. One source commented: "That's just a theory, but quite an attractive one."
Yet another is that the raid was intended as an assurance to republican rank and file members who were concerned that Sinn Fein and the IRA might be conceding too much in the pre-Christmas negotiations. The deal on offer at that point included total weapons IRA de-commissioning together with the installation of Mr Paisley - for decades a republican hate-figure - as First Minister.
At a deeper level, the suspicion exists that Mr Adams and Mr McGuinness may have lost control of the republican movement and that more militaristic elements are taking charge. Once again there is great doubt. One high- level source said: "Another question is how much control Adams and McGuinness have over the whole organisation."
This possibility is perhaps the one most concerning London and Dublin, since the entire peace process has been based on the principle of inclusion. An inclusive settlement is, however, regarded as impossible if republicans refuse to give up illegalities.Reuse content