Councillors have hit out at the secret terms of the settlement relating to the botched re-development of the William Penn Leisure Centre.

The work to improve swimming facilities in the Mill End centre began in early 2007 and was supposed to take less than a year and cost no more than £3 million to complete but a string of complications saw the budget rocket to more than £9 million while construction of the new facilities dragged on for more than three years.

Earlier this month a compensation package was agreed at a two-day behind-closed-doors mediation hearing between Three Rivers District Council, Gee Construction and project manager W S Atkins.

Sources say the council will receive roughly £700,000 in compensation from Atkins however officials this week refused a Freedom of Information request to disclose the settlement - citing a confidentiality agreement.

No liability for the disastrous project was accepted by any party but the council said it was "satisfied" with the compensation package and had been "vindicated in its claim not to be at fault in any way for the project over-runs".

Conservative leader Chris Hayward attacked the council’s refusal to disclose the true scale of the financial disaster.

He said: "I am appalled at the terms of the mediation settlement, having previously been given many assurances by the Liberal Democrat administration on the strength of the council's case. "The council tax payers of Three Rivers are entitled to know the whole truth of just how much public money has been lost.

"I am also very critical of the press release issued by the Council last week which is a travesty."

The statement from chief exec Steven Halls, reported in last week’s Watford Observer, said: "Through no fault of ours, this project cost nearly double its originally agreed price and, instead of taking a year, as planned and contracted, it took nearly three and half years, meaning that our young people missed eight terms of school swimming, and all of our local residents lost 286,000 attendances".

"Our aims at mediation were to strive to resolve the matter at that stage and avoid an expensive trial, to ensure we did not have to spend any further money than that already budgeted and to ensure we received some money back.

"We succeeded in all three of those aims. I now hope we can concentrate on future projects, rather than dealing with the past."

Atkins declined to comment on the settlement while Gee Construction did not reply to requests for comment.