Lord Rogers complained over unpaid fees

But Lord Rogers brought an action against the assembly, saying it owed his company in unpaid fees.

It is thought the assembly will now have to pay around �380,000 to the architect.

For their part, the assembly said RRP had seriously underestimated the overall cost of the building.

The assembly also claimed it had been misled over the terms of the contract, and had incurred serious costs as a result.

Although the judgement in the case accepted Lord Rogers had underestimated the costs, it felt this was not enough for the assembly to withhold fees.

The news is the latest development in a story which has unfolded over the last four years.

In 1998, RRP had agreed to build the Cardiff Bay debating chamber for �27m but costs subsequently rose to an estimated �37m to �41m.

Chamber pledge

The project has now been put out to tender, and Lord Rogers has teamed up with a construction group in a bid to win back the contract.

The RRP's design now has the backing of the housing, property and construction firm Taylor Woodrow.

Finance Minister Edwina Hart

The consortium also includes the international engineering firm Arup and building services engineer BDSP.

Lord Rogers has now pledged to build the new chamber for �13m.

The man behind the Pompidou Centre in Paris and the ill-fated Millennium Dome in London has said the assembly HQ was "one of the best buildings we have ever designed".

But there have been calls for the chamber project to be scrapped and the money to be spent on a new children's hospital instead.

However, Welsh Finance Minister Edwina Hart has committed herself to building a new chamber.

Completion of the building is now scheduled for the second quarter of 2004.