A radical rule to ensure cheap homes are built in Brighton and Hove has cost taxpayers thousands of pounds in legal bills.

So far, developers have successfully challenged the city council's policy which demands 40 per cent of any new development is "affordable" six times.

Builders appealing against planning refusal have won their cases because the rule is not in line with Government policy and has not been formally adopted by the council.

In the latest case, housing developer Gleeson Classic Homes has won an appeal to build 14 executive flats in Salisbury Road, Hove, leaving the authority to pick up the bill for legal costs on both sides.

The 40 per cent policy is part of the council's emerging Local Plan, which will govern future development in the city but it has not yet been officially introduced.

It was agreed as a popular measure to ensure homes were built for families who live and work locally, to tackle the city's growing housing crisis.

But Government rules stipulate affordable housing should only be built when more than 25 homes are being created. In the city council's policy, the number was lowered to ten.

Since June 2001 the emerging policy, called HO2, has failed six times.

Despite the rulings and the cost, the council has said it stands by the policy.

Chairman of the planning applications sub-committee Councillor Roy Pennington said: "The 40 per cent affordable housing policy is a response to the acute housing need in Brighton and Hove.

"There is an affordability gap in the city and many people on low to middle incomes are unable to get onto the housing ladder.

"When we were preparing the Local Plan for the new city, we knew we were above Government guidelines in this area but, significantly, many other local authorities have since adopted this policy to provide affordable housing."

But Gleeson Classic Homes has warned the policy could drive developers away.

Construction director Ben Coster said: "We appreciate there is a need for affordable housing in Brighton and Hove but some areas are just not suited to that type of accommodation."