Officials admitted a mixture of miscalculation and human error led to the county council losing £187,000 towards improving secondary education in Whittlesey.

The blunder has been revealed in a series of Freedom of Information requests – and extensive follow ups- by Mike Wollaston.

A joint statement by Cambridgeshire County Council and Fenland District Council admitted the mistake.

“We accept that an error was made in the calculation, which was made by the promoter of the site rather than by officers from Cambridgeshire County Council or Fenland District Council,” said the statement.

“Following an internal review by directors from both Councils in 2015, revised procedures for calculating and securing developer contributions have been introduced.”

Mr Wollaston is the chairman of Snowley Park residents group that unsuccessfully campaigned – along with local councillors and MP Steve Barclay- to halt 150 homes being built at Snowley Park and Glenfields.

The documents reveal that the education contribution was worked out after the initial application showed a likely mix of 50 one/two bedroom homes, 40 three bedroom homes and 30 four bedroom homes. Thirty others were deemed to be ‘affordable rent’. Another ‘indicative mix’ showed 67 one-two bed homes, 50 three bed homes and 33 four bed homes.

Using the council’s standard multipliers this gave a contribution of £26,800 that was written into the contracts.

“The final contribution was subsequently calculated by applying the number of secondary age children (thought to be 26) with the rates in the Fenland Council supplementary planning document (SPD),” said Georgina Fuller, business development officer.

Follow up questioning by Mr Wollaston revealed that when the application was later considered with more detailed plans (reserved matters) the total number of homes was finalised at 144.

However these were amended with the mix including only 30 one/two bed homes, with the number of three bed homes rising to 38, the number of four bed homes jumping to 71 and there were to be five 5 bedroom homes.

The secondary school contribution would have been £213,100.

In one letter Mr Wollaston asked the county council: “Could you please clarify if it was the case that a planning obligation (section 106) agreement was shown not to be correct or fit for purpose? What could be done to re-address the situation?”

Ms Fuller told him: “The calculation was subsequently found to be in error and the number of dwellings (not pupils) should have been the basis for the calculation.

“This error was identified after the issuing of the planning permission and therefore it was not possible to address the situation with the applicant.”

David Wilson Homes of Northampton has since started work on the housing estate.