The biggest investment in Birmingham’s council-run swimming pools for decades received political backing yesterday, but the politician in charge of delivering the vision has admitted he can’t yet be sure how the £90 million-plus transformation will be paid for.

Members of the city council cabinet gave their support to ambitious proposals that include building a 50 metre Olympic-size pool and water park along with refurbishment and replacement of other public baths. Leisure department officials have until September to come forward with detailed business cases for the Birmingham Aquatic and Leisure Centre, which will have the 50 metre pool as its centrepiece, and the rebuilding of Harborne baths.

Work is continuing on plans to replace Sparkhill pool, which has been closed for safety reasons, and to re-open the Edwardian Moseley Baths number one pool, which has been closed for years.

And in a surprise move, new leisure, sport and culture cabinet member Martin Mullaney announced that a proposal to replace or rebuild the Stechford Arcades baths was being brought forward and would be included in phase one of a wide-ranging strategy to improve public swimming provision in Birmingham.

But Coun Mullaney conceded it was unclear how the council would fund investment on such a scale, other than by increasing borrowing and raising money through land sales. Little more than one-third of the total cost of the baths programme has been identified.

Coun Mullaney (Lib Dem Moseley & Kings Heath) said: “I have been talking to my officers about where the money will come from and we intend to present a report to cabinet in September.”

Priority is being given to the Birmingham Aquatic and Leisure Centre, to be built on a site close to the National Indoor Arena in Ladywood, which the council wants to open by February 2012 before the London Olympic Games in the same year. It’s hoped that the provision boost Birmingham’s bid to host training camps for the games.

Harborne Pool is likely to open by December 2011, although the council admits the timetable is very tight. No decisions have been taken yet about Stechford Cascades and Moseley and Sparkhill baths, and it is by no means certain that all of the projects will go ahead as planned.