Rebel Conservatives last night launched an unprecedented bid to overturn their own party's awarding of a contract to build an incinerator in Norfolk.

Disgruntled Tories are angry that their own cabinet agreed to award a contract to build and run the plant on land at Saddlebow near King's Lynn, despite a poll showing more than 92pc of people in West Norfolk oppose it.

Now they have taken the extraordinary step of calling in their own leaders' decision for further probing next Tuesday (March 22), as has every other political group.

Council leader Derrick Murphy played down talk of a deep Conservative rift and suggested the actions of some of his colleagues might be motivated by forthcoming local council elections.

But behind the scenes he was on the phone to rebels, trying to persuade them to back down.

The county council cabinet last Monday agreed to award a 25-year contract to Cory Wheelabrator.

John Dobson, Conservative county councillor for Dersingham and a West Norfolk borough councillor branded that decision of his fellow Tories as a 'disgrace', because the poll conducted by West Norfolk council showed 65,000 people were against the plant.

He – along with fellow Conservative county councillors Brian Long, who represents King's Lynn North and Central, and Tony White, who represents Feltwell – has called in his own party's decision for scrutiny.

The move means the decision over the incinerator contracts will have to get through the extra hurdle of the county council's scrutiny committee, which can make recommendations to the ruling cabinet or ask for the decision to voted on by full council.

Mr Dobson said: 'I'm in politics to represent people – not force something down their throats they don't want.

'The findings [of the poll] were largely ignored by cabinet members, which flies in the face of the new localism.

'The whole thing is a disgrace. It's now down to Conservative councillors to speak out.'

West Norfolk council has also called an emergency meeting on Thursday night at King's Lynn Town Hall to discuss the award of the contract, but it is not yet clear what action, if any, the authority will take.

Mr Murphy, leader of Norfolk County Council, said the right decision for Norfolk had been made.

'If it hadn't been called in I would have been surprised,' he said.

'Call-ins are a pivotal part of the democratic process and it is right that a decision of this importance should receive such scrutiny.'

Of his own side calling the decision in, Mr Murphy played down talk of a rift, even though this is believed to be the first time a controlling group at County Hall has had one of its decisions called in by its own side.

Yesterday Mr Murphy telephoned Mr Long to ask him to reconsider backing the call-in, while an appeal to another councillor who had originally backed it succeeded.

Mr Murphy later said: 'I am perfectly happy with it. I live in the west and know how controversial it is.

'People in the west need to be sure that the process was properly handled. I know Mr Dobson has called it in and I note he was not there on Monday [when the decision was taken] and did not take the opportunity to ask questions.'

The county council has secured �169m of PFI credits from the government to help pay for the �500m project, which if it secures planning permission and environmental permits, is expected to process 170,000 tonnes of household waste and a further 90,000 tonnes of commercial waste.

Scrutiny committee chairman Paul Morse said his own Liberal Democrat party was calling in the decision, along with the Greens. Labour councillors have also called in the decision.

Membership of the scrutiny committee reflects the overall balance of power on the council, with Conservatives holding 12 of the 17 seats.

As it stands, the county council is expecting to sign the contract with Cory Wheelabrator, whose own survey of 1,700 people showed 65pc of people across Norfolk were in favour of the plant, within the next couple of weeks.

It will be down to the county council to decide whether planning permission should be granted. That has proved controversial, because a 'breakage cost' in the contract means County Hall could have to pay out up to �20m if the scheme does not go ahead.