Blair has faced vocal union criticism in recent months

Prime Minister Tony Blair agreed to the idea at a meeting with leading trade unionists in Downing Street.

Coming ahead of next week's TUC congress, the move will be seen as an attempt to stave off public disputes with the unions over public service reforms such as plans for foundation hospitals.

Tory shadow trade secretary Tim Yeo said Tony Blair was offering the trade unions "even more influence", despite "a summer of industrial unrest and over a million workdays lost to strikes in the last 12 months".

But TUC general secretary Brendan Barber said the forum was part of trying to get dialogue between unions and government on a more "structured and productive basis".

The best way of improving public services was if the government harnessed the support of public sector staff, said Mr Barber.

'No talking shop'

The forum will be chaired by Cabinet Office Minister Douglas Alexander, who will now discuss how the forum will work with Mr Barber.

Mr Barber continued: "This is not about access or privileges (for unions)...

"I do not think it's going to be a talking shop. It's going to be a mechanism where we have a serious dialogue, a real dialogue."

We have a lot of constructive work to build on Brendan Barber TUC general secretary

The government would be able to test its ideas, and get unions' reactions ahead of publishing plans, rather than presenting them with "fait accompli", he said.

The union leaders' meeting at Number 10 was one of a series of routine summits.

But it was given added significance as critical motions loom at next week's congress on issues such as foundation hospitals, pensions, transport policy and the ban on secondary strike action.

Recent months have seen left-wing union leaders especially vocal in their criticisms of the government.

'Progress through agreement'

Earlier on Tuesday, Health Secretary John Reid indicated the government would not be backing down on its foundation hospital plans, which would give hospitals more freedoms.

Patients' interests had to come first, said Dr Reid.

But Mr Barber argued there had been significant progress through agreement in recent months on such issues as the two-tier workforce in local government and on schools' changes.

"We have a lot of constructive work to build on," he said.

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On Monday, the head of the big business organisation, the CBI, Digby Jones, accused the unions of blocking public service reform - and he suggested employers and unions were growing apart.

Foundation hospitals top the unions' list of concerns on public services.

Ahead of the meeting Jack Dromey, from the Transport and General Workers' Union, told BBC Radio 4's Today programme: "We will ask the prime minister to abandon the ill-thought out concept of foundation hospitals - something which was not in Labour's election manifesto.

"Foundation hospitals could be Labour's poll tax."

Mr Dromey argued that the plans would set "nurse against nurse" and urged the government to guarantee that any foundation hospitals which were set up would have to stick to national pay rates.

Friction warning

Unison general secretary Dave Prentis said the unions hoped the reform arguments would not lead to bad relations with the government.

But he warned: "If the government doesn't talk to us, doesn't listen, I can see friction increasing."

Business chiefs from the Multinational Chairmen's Group also met the prime minister at Downing Street on Tuesday.