The deadlock over who will run Norfolk County Council could be broken today, after a rainbow alliance was formed which could usher in a Labour leader at County Hall.

A deal has been agreed between Labour, the UK Independence Party and the Liberal Democrats, which could end the stalemate which has gripped the authority since the county council elections three weeks ago.

Those three parties have come together to back Labour group leader George Nobbs as the new leader of the county council, on a mandate to shake-up the way the council operates.

The unlikely alliance, which the three parties have insisted is an agreement, not a coalition, is predicated on one issue - that the cabinet system is scrapped and a committee system brought back to County Hall.

An extraordinary meeting of the county council will take place today in an attempt to find a leader and Mr Nobbs has positioned himself as a 'reform candidate'.

He says, if elected, he will serve for one year, the time it would take to change the way the council is run back to a committee system, and will then step down.

Labour, the Lib Dems and UKIP say a committee system would be more democratic and prevent important decisions, such as the former Conservative cabinet's controversial one to award a contract for the King's Lynn incinerator, from not going to full council.

But the chances of Mr Nobbs succeeding in his leadership bid could be out of the hands of the 'rainbow alliance'. Assuming the three parties in the alliance back him, but the Conservatives vote against him, it would come down to the four-strong Green group.

And the Greens dropped out of the talks to form the alliance earlier this week, so there is no guarantee they will back him at today's meeting.

At a press conference at County Hall yesterday, Mr Nobbs described himself as a 'reform candidate' and said the resolution for change would be presented at today's meeting.

He said: 'We propose to change the system by which Norfolk County Council is run, where decisions are made not by the whole council, but by the cabinet.' On the alliance, he said: 'It's taken us some time, but I think it is all worthwhile. Of course we have differences between us politically, but we are united on this one thing.

'This council needs to change the way it does business. I am a reform candidate.'

Toby Coke, leader of the UKIP group, said: 'We have made a huge step forward in being united in this aim. It would be a completely democratic system. We have seen the deficiencies in the cabinet system, the most obvious being in the decision over the incinerator.' Mr Nobbs said: 'Never again can there be a decision on something like the incinerator or unitary status without councillors having a vote on it.' James Joyce, deputy leader of the Lib Dems, acknowledged the unusual trinity. He said: 'If you'd asked me before the elections, did you ever envisage parties like us working together I'd have said no.

'But people felt democracy had disappeared a bit last time around. We have to get the democratic voice back into the council, so every single councillors has a say on what they believe in and stands up for what they believe in.'

Mr Nobbs said if he does become leader, he would pick his cabinet from the best candidates available. But it is understood that UKIP will not be seeking any cabinet posts.

However, Richard Bearman, leader of the Green group, was last night tight-lipped about whether the rainbow alliance would get his group's support.

He said: 'We were set to sign the resolution but we have not agreed to do so. We do support the move to a committee system. However, what we are not comfortable with are the details. We do not have details of what would happen under a George Nobbs administration.' When asked how Green councillors would vote, Mr Bearman said that was a decision which should be made in the council chamber.

Last week, an attempt by the Conservative group to form a minority administration, led by former council leader Bill Borrett, was defeated.

The Conservatives have put forward their own motion for today's meeting, which they say is 'focused to deliver the best possible solution for the people of Norfolk'.

That is for an all party group to be set up to look at 'all possible systems', including the committee system, to pick which one is best for the county.

Mr Borrett said his group would not be supporting the proposal by Mr Nobbs. He said: 'I respect him putting himself forward for leader, but by my calculations he has a coalition of 39, so I'm interested to know if this is to be a minority administration. 'I'm also interested to know what his policies would be, in terms of the services which Norfolk County Council offers.'

The county council has been stuck in limbo since the results of the May 2 election, when all 84 council divisions were up for election. The Conservatives saw their majority whittled away at the ballot box, with their number reduced from the 60 at the 2009 elections to 40.

UKIP's success was the big surprise, increasing their number of councillors from one to 15. Labour made gains and took 14 divisions, although that was not as many as the party had hoped. The Liberal Democrats have 10 councillors, the Greens four and there is one independent.

Today's meeting takes place at 10am at County Hall.