Permanent secretaries are gossiping, with the rumours running through Whitehall that Mr Blair would return intent on reshuffling the pack at Whitsun during the MPs' 11-day Easter break in advance of the Government's first anniversary in office on 1 May.
The one key figure in the entire jigsaw is Alistair Darling, Chief Secretary to the Treasury, and, as he is in the middle of his comprehensive spending review, which will not be complete until July, the odds are against the reshuffle next week. That could leave Whitsun, at the end of May, as the more likely opportunity. It would allow a move for Mo Mowlam, the Northern Ireland Secretary, after a referendum on the peace plan.
Mr Blair is due to spend part of his Easter break in Cordoba, Spain, before an official visit to Israel at the end of next week.
Some senior ministers nevertheless are braced for a snap shuffle next week, and there is an intense game in Whitehall of ministerial `snakes and ladders' going on to guess who is going up, and who is going down.
Peter Mandelson, the "Dome Minister", is widely believed to be the first on the ladder into the Cabinet. He is being tipped to replace David Clark as Chancellor of the Duchy of Lancaster, in the Cabinet office to remain in charge of the Millennium Experience project.
Hilary Armstrong, minister of state for local government, is also regarded as being highly competent, with the ability to hold down a top job in the Cabinet. If he moves his chief whip, Nick Brown, Mr Blair could promote Peter Kilfoyle, parliamentary under-secretary for the Cabinet office, into the job. "Peter is a real killer. He will not tolerate indiscipline," said a source. Geoff Hoon, Parliamentary secretary for the Lord Chancellor's office, is also on the ladder to minister of state rank.
Mr Blair is also expected to promote a number of `new intake' MPs to the front bench. Those threatened with the slippery slide out of the Cabinet with Mr Clark include Gavin Strang, transport minister. But rumours suggest Mr Blair is also keen to freshen up the team with more changes, including a move for Ann Taylor, Leader of the House, and Nick Brown, chief whip.
The Prime Minister's office has been dismissing talk of reshuffles for some time, but the strength of the rumours now running around Whitehall has led to some ministers doing their best to check on their veracity. "We thought it couldn't be true, but we have been told to stand by," said a ministerial source. One advantage of holding a surprise reshuffle next week could be entirely presentational - it would reinforce Mr Blair's stamp on the Government, and out-flank the critics who may be gearing up to give Mr Blair a hard end-of-term report for the Government's first 12 months in office.