Another firm has been brought into a major court battle over what went wrong with work on Bath's spa project.

Building firm Carillion and Bath and North East Somerset Council are suing each other over the extra costs and delays affecting the £45 million attraction, which finally opened in August 2006.

Now Carillion has filed a writ against sub-contractor Skanska, claiming its work was defective, ahead of an eight-week case likely to begin early next year.

The main dispute centres on claims that peeling paint and waterproofing problems set back the already badly delayed flagship project even further and cost millions to put right.

Carillion is claiming it is owed £2.382 million by B&NES and the council is counter-claiming for £21.366 million.

The row broke out as long ago as April 2005 after problems were identified with the painting of the spa pool and waterproofing.

The council ordered Carillion's subsidiary Mowlem off the project.

Carillion claims the pool paint and waterproofing problems were "due to inadequate specification and design", and the council has passed on this claim to the project's architects, Nicholas Grimshaw & Partners Ltd meaning that firm is now involved as a third party in the litigation.

According to the website Construction News, Carillion has filed a writ in the Technology and Construction Court in London saying that "elements of" the mechanical, electrical and fireproofing work carried out by a Skanska subsidiary "were defective and required extensive remedial works."

It is not clear what sum Carillion is looking for from Skanska.

Skanska said: "The matter is subject to legal proceedings and we are unable to comment further at this time."