By political correspondent Nick Assinder

All the spin doctoring in the world cannot hide the fact that Deputy Prime Minister John Prescott has been deprived of a huge part of his powerbase by Tony Blair.

There were clear signs that his number was up when the prime minister first appointed Lord Macdonald to the transport brief in the summer cabinet reshuffle.

At the time he was accused of being Tony Blair's "spy in the cab" at the transport department.

Now that the prime minister's patience has finally run out with Mr Prescott, Lord Macdonald has effectively been appointed as transport secretary.

That reshuffle also saw two of Mr Prescott's closest supporters - Alan Meale and Richard Caborn - removed from his department, significantly weakening his power base.

It is also claimed that Mr Prescott's role as deputy prime minister has been diminished over the months and that Chancellor Gordon Brown and Northern Ireland Secretary Peter Mandelson are effectively acting as joint deputies.

And, for the second time in a week, there are serious questions being asked about Mr Prescott's long-term future.

No change

Lord Macdonald and Downing Street have tried to insist that there has been no change in the power structure in the rambling Department of the Environment, Transport and the Regions.

But if that was the case, there would be no need to announce that Lord Macdonald is taking over the day-to-day running of the transport brief.

The prime minister has become increasingly frustrated at the alleged mishandling of transport policy and a series of PR blunders by Mr Prescott has not helped.

Lord Macdonald is seen as a safe pair of hands who will be able to handle the media in such a hugely-sensitive area.

He is one of the so-called "Tony's cronies" who have been appointed to top jobs, rather than being elected.

And that has led to widespread disquiet on all sides of the Commons. Some Labour backbenchers are angry that unelected individuals with little or no accountability to the Commons are being put in charge of key policy areas.

Many were already speculating that Mr Prescott would not survive in cabinet after the next election and a few even believed the prime minister would act beforehand.

It now appears Mr Blair's tactic is to gradually weaken Mr Prescott by diverting power and responsibility away from him.

Malicious stories

The deputy prime minister, meanwhile, is complaining that it is some sections of the media which are out to get him and fanning all the speculation about his future.

But it is not that long ago that he was blaming Downing Street insiders for spreading malicious stories about his competence and long-term future.

Mr Prescott's great strength - which has been relied upon by three party leaders - has always been to keep Old Labour on side through the modernisation of the party.

Mr Blair undoubtedly wants him to continue doing that in the run up to the next general election where the behaviour of core Labour voters will be crucial.

But is also appears clear he had lost the prime minister's confidence in the transport brief and many believe he may be given a different, organisational role once the election campaign is in full swing.