The cost of pulling the plug on Norfolk's incinerator could be more than £100m, according to a report drawn up by an independent financial consultancy.

The figure is the latest to be put forward in a series of reports published ahead of a decision on the future of the proposed King's Lynn incinerator on Monday.

Defra announced last week it had cancelled the waste credits for the controversial plant. The previous administration at County Hall had agreed a contract with Cory Wheelabrator to run it.

Those credits would have been worth £169m over the lifetime of the plant, but campaigners say the withdrawal means now is the time to pull the plug on the plant, which 65,000 people in West Norfolk had opposed in a poll organised by the borough council.

The full county council will, on Monday, decide whether to agree a revised project plan for the plant. Officers say that rejecting that would trigger costs payable to Cory Wheelabrator of £25.9m.

The latest predicted compensation figures are put forward in a report from consultants PriceWaterhouseCoopers.

They say that if the council pulls the plug on the scheme, there would be an estimated compensation payable of £28m.

But they add that Cory Wheelabrator may try to argue that the contract entitles them to a return on all the money the contractor would have invested during the life of the contract.

They say: 'Whilst we cannot estimate with certainty what this amount may be, our best estimate at present is that it would be in excess of £100m.'

And they say that if the plant is not built because the secretary of state refused to ratify planning permission, that would lead to compensation of around £24.7m.

But the report also carries the caveat that the consultants were not in full possession of the facts,

They say: 'We have not been able to calculate precisely the amount of compensation payable,,, because most of the information we needed to calculate amounts payable under the contract has not been provided by the contractor and some of the amounts that fall to be included do not crystallise until the actual termination date or later.'

The report was commissioned by the county council's cabinet and the consultants were selected by anti-incinerator campaigners.

Defra announced last week it had cancelled the waste credits for the controversial plant. The previous administration at County Hall had agreed a contract with Cory Wheelabrator to run it.

Those credits would have been worth £169m over the lifetime of the plant, but campaigners say the withdrawal means now is the time to pull the plug on the plant, which 65,000 people in West Norfolk had opposed in a poll organised by the borough council.

The full county council will, on Monday, decide whether to agree a revised project plan for the plant. Officers say that rejecting that would trigger costs payable to Cory Wheelabrator of £25.9m.

And Peter Timmins, interim head of finance, said, in another report which will come before councillors, that is 'a financial step too far.'

He said it would mean he would have to serve a section 114 notice on the authority - designed to prevent the authority doing something unlawful or facing the prospect of bankruptcy.

While opponents have questioned why the council cannot use its reserves to make the payment, the council insists that is not an option.