A new housing strategy which critics believe threatens Newmarket's position as "the capital of the horseracing industry" has been declared legally flawed by the High Court.
Leading names in the racing world asked a judge to quash a decision to adopt the Forest Heath Core Strategy Development Plan, arguing it could destroy the unique, horse-friendly character of the Suffolk town.
Mr Justice Collins, sitting in London, allowed the challenge and ruled that, in adopting the new strategy, there had been a failure to comply with an EU planning directive.
The judge quashed the proposed central housing policy of the core strategy as it affects Newmarket.
He ruled there had been a failure to comply with the relevant directive because a strategic environmental assessment did not contain all the information it should have done.
As a result, it was not possible for those consulted over the proposals to know the reasons for rejecting any alternatives to the policy as it affected Newmarket, said the judge.
His ruling was a blow to Forest Heath District Council, which adopted the new housing strategy in May last year. The council was refused permission to appeal.
It was also a blow to Lord Derby, whose family gave its name to the world's most famous flat race. He had supported the new strategy and controversially applied for permission for 1,200 new homes on his Hatchfield Farm property north-east of Newmarket.
His planning application was refused, but the appeal process is continuing and could be affected by Friday's High Court decision.
The ruling was a victory for the Save Historic Newmarket Ltd (SHNL) campaign group, which was supported by the Jockey Club, auctioneer Tattersalls, commentators Sir Peter O'Sullevan and Clare Balding and other leading figures in the racing world who claimed the proposed urban development would ultimately lead to the demise of Newmarket as a racing centre.