Mrs Spelman had withheld �169m of private finance credits from Norfolk County Council because of concerns about the proposals for an incinerator at King's Lynn.

But it is understood she will say next week she will award the credits, having been convinced the majority of council leaders in Norfolk support the waste strategy of which the Saddlebow plant is a key part.

That is likely to see opponents switch their attention to the planning process, with the county council's own planning committee set to decide whether to give permission for the plant.

Elizabeth Truss, MP for South West Norfolk, who, along with Henry Bellingham, MP for North West Norfolk, has opposed the incinerator, admitted last night she feared Mrs Spelman was about to give the green light for the PFI funding.

After speaking to the minister she said: 'I am concerned about the content of the announcement. I made the point that people in South West Norfolk do not want the credits to be awarded unless there is a significant change in the proposals.

'I would have liked to have seen Defra (Department for Environment, Food and Rural Affairs) working with councils involved to come up with a different solution.

'If the PFI credits are awarded the next stage is the planning process and raising the issue with Communities Secretary Eric Pickles.'

Mrs Spelman announced in November she was withholding the PFI credits and told County Hall she wanted to see more evidence of 'broad support' for its proposed waste strategy. That led to a number of district councils writing letters to Mrs Spelman supporting the waste strategy, though West Norfolk Council leader Nick Daubney and some opposition leaders on district councils pleaded with her not to be swayed.

Bill Borrett, cabinet member for environment and waste on Norfolk County Council, said: 'I am hopeful we will get the money because we have done everything that we were asked to do. 'I am sure we have played it by the book all the way through and I'd be more surprised if we did not get the PFI credits.

'This whole project is all about saving money. The only reason we have embarked on this project is to save tens of millions of pounds, and I am not surprised that the districts have supported us. These are lean times for local government and all councils are trying to save money.'

Mr Bellingham said a public inquiry was necessary, adding: 'I would hope very much Mr Pickles will call it in, appoint an inspector to hear it in a public inquiry and then everybody will have their say.

'It is currently going through the county council planning process. Their planning committee will deliberate on the application. Now I don't think anyone in Norfolk would have any faith in that arrangement.'

Meanwhile county councillors yesterday unanimously agreed they needed to visit the site of the proposed plant, which will cost more than �500m, before making a decision.

The planning regulatory committee has yet to fix a date for when to head to Saddlebow but chairman John Rogers urged members not to get embroiled in conversations about the plant in advance.

A committee report said: 'At the time of writing, 2,639 representations had been received, of which 2,550 (96.6pc) have objected to the proposal. Given this level of objection, the proposal can be considered to be controversial.

'The site visit would be a fact-finding visit to enable members to note relevant features pertaining to the site and to gain an appreciation of the scale of the proposal in the relation to its surroundings.'

The county council says the plant is needed to prevent the county's waste having to go to landfill. It says it will save millions of pounds a year.

But in a poll conducted by West Norfolk Council, 65,000 people said they did not want the plant.

Anti-incinerator campaigners last month attempted to secure a judicial review into the process by which the county council agreed to award a contract to waste company Cory Wheelabrator but a High Court judge dismissed their attempt.

dan.grimmer@archant.co.uk