THREE senior Sinn Fein figures, including party president Gerry Adams, have stepped down from their posts on the IRA's ruling army council.
The ground-breaking decision means that all links between the leadership of the political and military wings of the Provisional movement have been severed.
And it paves the way for major changes in the Provisional structures to be announced in an IRA statement, now expected to be delivered in the second half of next week.
It is believed that the internal IRA debate about its future, which has been going on for over three months, has now effectively ended and that the final details of the statement are being worked on.
It was learned last night that Mr Adams, Sinn Fein's chief peace negotiator Martin McGuinness and Dail deputy and convicted gun-runner Martin Ferris have all resigned from the seven-man IRA army council.
Their posts have been filled by two men from Belfast and one from Tyrone, all of whom are closely aligned to the Adams-McGuinness group pushing the movement onto a purely political path.
The changes in personnel are also seen as part of the "sanitisation" process within Sinn Fein as the party prepares to present itself as a democratic body that is ready to play a full part in political developments north and south of the Border.
None of the new appointees is a member of Sinn Fein but all are regarded within the Provisionals as militarists with proven records.
One of them is a hunger striker from Belfast and he has been on the IRA's headquarters staff with responsibility for the "engineering" department.
The second is also from Belfast and had criminal convictions in the past for possession of explosives, while the third is regarded as the IRA commander in the Tyrone region.
The make-up of the rest of the army council remains unchanged and South Armagh hardliner Tom "Slab" Murphy continues as the organisation's chief of staff, a post he has held since an IRA executive meeting in Falcarragh, Co Donegal, in October 1997 - a summit which resulted in the resignation of Michael McKevitt and the subsequent formation of the dissident Real IRA.
Speculation about radical personnel moves within the IRA have been rife since Mr Adams started a series of internal discussions at all levels of the Provisional movement with his suggestion that it should abandon all paramilitarism and concentrate exclusively on the political path forward.
Intelligence sources last night confirmed that the changes had taken place and described them as the biggest shake-up at the top in the past eight years.
With no overlapping at leadership level, Sinn Fein figures can now argue that the two wings of the movement cannot be accused of being "joined at the hip", although the new army council members are regarded as totally loyal to Adams-McGuinness - where the real Provisional power base remains.
The appointments also mean that seven militarists will be seen as approving the change of direction to be announced in the imminent statement from the IRA rather than coming from a council dominated by Sinn Fein figures.
In the wake of the London bombings, and with an increasingly hostile climate both here and in Britain towards terrorist violence, the Provisional movement is understood to have decided that this is the right time to move into a new mode.
Since Taoiseach Bertie Ahern and Foreign Affairs Minister Dermot Ahern had an hour-long meeting in Drumcondra eight days ago with Mr Adams, things have moved quickly.
It is known that contacts between the Government and Sinn Fein have been continuing in the background on a daily basis as hopes have again arisen of a positive statement.
Final acts of decommissioning by the movement would be a key part of the expected statement, which has been delayed partly because of difficulties around the Twelfth of July Orange parades and by the return to jail by Northern Secretary Peter Hain of Shankill bomber Sean Kelly.
It is understood most of the IRA stockpile of weaponry is now located at a couple of arms dumps and could be disposed of quickly.
Former Canadian General, John de Chastelain, who heads the International Independent Commission on Decommissioning, is known to be in Ireland at the moment.
His word would be necessary for the independent verification of arms disposal, as with earlier acts of decommissioning by the IRA.
An IRA statement declaring an end to paramilitarism and criminality could also help pave the way for the restoration of the Northern institutions, although the DUP would be unlikely to engage in talks with Sinn Fein until early next year at the earliest.
Dr Ian Paisley and other senior Unionists have expressed scepticism about whether the IRA statement would go so far as to call a final halt to all paramilitary operations.
And it would wait for assurances from the International Monitoring Commission over a period of several months that all IRA paramilitary activity, recruitment and surveillance had completely stopped before going into talks.