An investigation has been launched by Richmond Council after confidential financial information about Twickenham Riverside development was leaked.

Documents, which showed how much of the profit from the development would be split between the council and preferred developer Countryside, were posted through Fifth Cross Road resident John Reekie’s door this week.

The papers, detailing financial arrangements for the old baths site, where the council wants to see luxury housing built to pay for an educational riverside centre, were then passed to the Richmond and Twickenham Times.

The leaked information also shows how much the housing each of the three bidding developers had proposed would cost, per square foot.

The figures have led Twickenham Riverside and Terrace Group (TRTG) to argue the development would consist of low cost, “Lego-style”, prefabricated buildings.

Mr Reekie, chairman of the TRTG, explained he was grateful to the unknown person who had leaked him the information as it provided figures he said were not previously revealed in public meetings.

He also added he had been unable to see any accounts for Countryside since September 2007.”

TRTG member Scott Naylor said: “This looks like they are going for the most profitable one. The housing will look like Lego. It will be Brentford gone wrong. Pre-fabbed boxes. Quality costs, and the cost of these properties are below a good level.

“How can they make the level of build, when the other developers have not been able to?”

Deputy leader of the Conservative opposition Geoffrey Samuel feels the riverside saga is getting “worse and worse”.

He said: “First the council wants to hand over an unwanted £3m building free, then we have a business plan so open to ridicule it has to be hushed up.

“Then the chosen developer, which will build 32 high-rise, luxury buildings on public land, has a record which scrutiny will need to investigate.

Coun Samuels added he was concerned that there had been a lack of public involvement in the decisions over the site as financial information had been kept secret because of its commercial sensitivity.

A spokesman for the council said it took the leaking of confidential papers by either officers or councillors as a serious matter .

He added that where those responsible are identified, the council would pursue action under its disciplinary procedures for officers and code of conduct for councillors and, where appropriate, refer them to the Standards Board for England.