By Ollie Stone-Lee Political reporter, BBC News

Tony Blair could face a rough ride at the TUC

Labour cannot reconnect with its supporters until it gets a new leader, the head of Britain's trade union movement has said.

Trades Union Congress chief Brendan Barber said Mr Blair's announcement that he will step down by this time next year had helped clear the "fog".

But ahead of next week's TUC congress, he said "prolonged uncertainty" was hampering the government.

Mr Barber stopped short of saying Mr Blair should resign now.

Amicus leader Derek Simpson has, however, made that demand, saying Labour risks losing the next election unless there are changes.

In a briefing with journalists, Mr Barber said a precise departure timetable for Mr Blair was not yet clear.

"As the prime minister continues to consider this - and it is for him to decide - I'm sure he'll be reflecting on the dangers of prolonged uncertainty undermining the government's effectiveness," he said.

Mr Barber said Labour needed a fresh start and needs to redefine its core mission.

"It can only be the new leadership that can authoritatively articulate that new vision able to lift and inspire and re-energise the government's supporters," said Mr Barber.

Inspiration needed

Mr Barber said the prime minister had made some serious mistakes but had won three historic election victories for Labour and made an "outstanding contribution".

He suggested that reputation could be damaged the longer he stayed.

"I regret the fact that the way the atmosphere is developing at the moment there may be a loss of perspective about the contribution he has made," he said.

Brendan Barber wants the uncertainty to end

A leaked memo written by allies of Mr Blair, including his pollster, laid out plans for a farewell tour to ensure the prime minister left with "the crowds wanting more".

Downing Street says the prime minister has not seen the memo and Mr Barber said any talk of a wave of euphoria was "just silly".

He said he had read reports about the memo with a "sense of wonderment".

Union influence

Mr Barber refused to outline the timetable he wanted for the prime minister to quit.

But he called for a real "sense of urgency" for addressing continued problems of inequality and "desperate poverty".

The prime minister will address the TUC in Brighton on Tuesday and face questions from union delegates.

Mr Barber said the congress would give unions the chance to have their say on Labour's future plans at a time when there were "flashpoints".

The unions have a third of the votes in any leadership contest and, with Labour facing large debts, their funding is seen as increasingly essential.

Public services anger

The biggest four unions - Unison, the Transport and General Workers Union, Amicus and the GMB - are holding a congress fringe meeting entitled "new leader, new agenda" as they look to the post-Blair era.

But in a clear dig at former ministers Stephen Byers and Alan Milburn, Mr Barber warned the prime minister's allies not to try to bind his successor to a Blairite strategy for the future.

"People used to talk about back seat drivers, that's out of date," he said. "Now perhaps we have to say that you can't nobble your successor's satnav.

"It would be like Sven-Goran Eriksson trying to dictate to Steve McLaren in advance the tactics and team selection for the European Championships campaign."

The congress will see anger about some of the government's flagship policies for schools, hospitals and other public services, which union bosses say often amounts to privatisation.

They are launching a campaign to defend the NHS which will culminate in a major rally at Labour's conference later this month and a lobby of Parliament in the autumn.

Mr Barber welcomed the extra investment put in by Labour but accused ministers of a "style of almost permanent revolution, and a dogmatic preference for the private sector".

"I despair at how difficult it can be to get real government engagement in constructive, intelligence dialogue with their own dedicated workforce," he said.

"The collapse in morale of NHS staff is tangible."