Firefighters have been striking for months

The Fire Brigades' Union executive had recommended the package proposing a 16% rise linked to modernisation, and as a result called off a 24-hour walk out planned for Thursday.

The leader of the FBU, Andy Gilchrist, said he thought the offer was the best available in the current political situation.

I don't see it as humiliating. It's proof that this is a truly democratic union Andy Gilchrist FBU leader

But his members disagreed, and accused the union's leadership of stabbing them in the back at a heated meeting on Wednesday.

A resolution calling for the latest offer to be rejected in the strongest possible terms was overwhelmingly passed by the delegates.

BBC correspondent Stephen Cape said some outsiders would see the vote as an embarrassment.

But Mr Gilchrist denied it, saying: "I don't see it as humiliating. It's proof that this is a truly democratic union."

Industrial action

The proposed deal will now be discussed by firefighters across the country over the next fortnight.

Another national conference will then be held to decide whether to accept it or continue with a campaign of industrial action.

Mr Gilchrist said the "logic" of the day's events meant that if the FBU's grassroots' membership agreed the deal was unacceptable, further strike dates would be set.

Heated debated and disagreement in the FBU was "quite usual", he added.

Nothing has changed from the original offer - all that has happened is that they have moved a few words around and that's it Tennyson Turney Cambridgeshire FBU

Delegates' fury with their leaders was clear as they gathered before Wednesday's closed-door meeting.

Tennyson Turney of the Cambridgeshire FBU, said he was "very, very angry" at the acceptance of "an appalling offer".

He said the executive council (EC) deserved a "damn good kicking".

"The EC needs to be looking at their position because if they are not in it for us then they should get out."

Ben Heanue, FBU branch secretary in Derbyshire, said text and telephone messages had flooded into his phone from his members protesting at the executive's decision.

Delegates were handed a leaflet by activists saying they had two choices - standing by union members who had fought hard during the campaign or "abject surrender" to a "rubbish" offer.

The FBU insisted the tone of the revised deal was "completely different" from an earlier one rejected by the union.

But it is understood the union's executive council was concerned that with war looming, Thursday's strike would turn into a public relations disaster as military units based in Britain were forced onto the streets to cover for firefighters.

Officially any link was played down, although Mr Gilchrist conceded the offer was not the best his executive could have achieved but the best "in the political situation they find themselves in".

Informal discussions

Tuesday's decision to call off the next 24-hour strike - called "very encouraging" by a spokesman for Deputy Prime Minister John Prescott - came after secret talks between FBU officials and local authority employers at the conciliation service Acas on Monday.

Over the weekend the two sides also held informal discussions. Mr Prescott was kept closely informed about the talks but did not take part directly.

The revised offer was then debated by the union executive, which voted 12-6 to recommend acceptance.

John Ransford, of the Local Government Association, denied the offer represented a "fudge", as it contained no precise details of what modernisation measures would be implemented.

Speaking on BBC Radio 4's Today programme, he said "fudging" the settlement would have only led to more arguments.