Norfolk County Council ignored Whitehall warnings there could be costly planning delays for the King's Lynn incinerator, it has emerged in a government spending watchdog report.

The National Audit Office said the Norfolk authority was challenged in 2010 over its compensation arrangements by the Department for Food, Environment and Rural Affairs, but the council still decided to press ahead with a contract which has left Norfolk taxpayers footing a £33.7m bill.

The council voted in April to pull the plug on a contract with Cory Wheelabrator to build and run the £610m plant at Saddlebow in King's Lynn, after officers said a delay in a decision from communities secretary Eric Pickles on whether it could go ahead meant it no longer offered value for money and the government pulled a grant worth £169m.

North-West Norfolk MP Henry Bellingham, who has been strongly opposed to the incinerator plans, said the 'damning' report showed there was a 'degree of arrogance' on the part of the council, which he claimed had thought it could just give the project planning permission without the decision being taken to central government.

But George Nobbs, leader of Norfolk County Council, said Defra had approved the contract and awarded Norfolk PFI credits worth £169m in the full knowledge of the proposed timetable and the compensation arrangements.

'By anyone's book, a two-year period for achieving planning permission should have been reasonable, and increasing that timescale would have increased the price of the contract,' he said.

The National Audit Office report, which also examined incinerator projects in Surrey, Herefordshire and Worcestershire, said: 'In the light of its concerns about Norfolk's proposed timetable for achieving planning permission, the department challenged Norfolk over whether it had fully considered the impact of not achieving planning permission on its proposed funding and compensation arrangements.

'Norfolk confirmed to the department that it had considered this and expected to achieve planning permission within the proposed timetable.

'On the basis that this risk was a matter for the council to judge, since it would bear the consequences, the department did not challenge this further.'

South-West Norfolk MP Elizabeth Truss said: 'I am concerned by this report and I believe that NCC officers need to present a clear account of what happened.

'Norfolk tax payers are having to foot the bill for this failed scheme; complete transparency needs to prevail and not be concealed behind corporate confidentiality.'