Councillors traded insults last night before agreeing a full and independent investigation into the William Penn Leisure Centre “disaster”.

As work on two new swimming pools sinks two years behind schedule and costs continue to spiral, project managers Three Rivers District Council accepted last night the need for a full and independent investigation when the project is finally completed.

Swimmers, however, were no closer to discovering when this will be, as the ruling Liberal Democrat administration again said it could not give an estimated opening date.

Councillor Chris Whately-Smith, leisure portfolio holder, said: “Progress is maintained but until the pool filtration system is tested, which can’t be done until the pool is filled, we are reluctant to confirm a date.”

The council’s main opposition Conservative group again used the debate to criticise heavily the ruling party.

Councillor Chris Hayward said: “This whole ghastly mess would be better than a West End farce if it wasn’t so terribly, terribly serious.

“Three Rivers residents deserve explanations and reassurances and they need to get those from a truly independent and trusted source.

“We are not prepared to see some cosy, clandestine internal scrutiny committee set up post this disaster giving a whitewash to our residents.”

Councillor Amrit Mediratta compared the council’s handling of the project to “the bumbling Mr Bean” and again criticised the alleged legal secrecy preventing full public debate.

Angry Liberal Democrat Councillor Sara Bedford, however, accused the Tories of political opportunism and stressed that her party fully shared their desire for an open and transparent investigation. There was, she said, no need for another round of arguments.

The motion was later approved unanimously.

Work continues at the site, in Shepherds Lane, Mill End.