By Nick Assinder Political correspondent, BBC News website

Tony Blair always feared that by announcing a timetable for his resignation, his government would be paralysed.

Whitehall is likely to slow down

Big policy developments on issues such as pensions, social exclusion, the respect agenda and even the approach to Iraq would be thrown into doubt as MPs, ministers and, crucially, civil servants pressed the pause button.

Gordon Brown may have expressed support for many of these policies and has gone further, by throwing his weight behind replacement of the Trident nuclear programme, for example.

He has also signalled that he is just as committed to public sector reform as Tony Blair - reminding people he was, after all, one of the architects of New Labour.

But the truth is, until the new prime minister has his feet firmly under the top spot at the coffin-shaped cabinet table, no-one can be absolutely certain what he or she really has in mind for the country.

And, of course, it may even be premature for MPs and civil servants to make the assumption that they will be working to Mr Brown.

Some doubt

So the obvious tendency on the frontbenches and in Whitehall is for a slowdown, a period of stagnation until the new boss has moved in, picked his Cabinet and got down to work.

Gordon Brown has backed many Blairite policies

Even the Queen's speech in November, which sets out the government's programme of legislation for the forthcoming session, must be thrown into some doubt.

What this may mean for planned legislation is, frankly, anybody's guess. But it almost certainly means that anything the prime minister announces between now and his actual resignation can be discounted.

Indeed, one of the demands from Blairites looking towards a possible Brown premiership was for some clarity from the chancellor on the approach he might take to key policies on, for example, the NHS, education and foreign affairs.

And whatever noises he has so far made on these core issues, he has characteristically avoided making any real commitments.

Other possible candidates are even more unknown quantities.

This is precisely what Mr Blair did not want to happen, of course. He is desperate to see his final months in power finally embedding "Blairism" into both the Labour party and the country.

He has run out of time to ensure that and it is likely the next few weeks or months will see plenty of talk about policy development and continuing reform - but it will all be taken with a large pinch of salt.