Senior Labour politicians have called on the government to end a tax loophole that allowed a billionaire to pay approximately £18mn less in stamp duty when buying one of Britain's most expensive houses. Suneil Setiya, co-founder of Quadrature Capital, bought a £275mn mansion in Chelsea from property tycoon Nick Candy and his former wife. If treated as a residential property, Setiya would have owed about £32mn in stamp duty. However, because the mansion was sold with five nearby flats, the UK's "six-plus" rule treated it as a commercial deal, with a top rate of just 5%, reducing the bill to about £13mn.

Baroness Margaret Hodge, the government's anti-corruption champion, urged authorities to close the loophole quickly. "It never fails to astound me how greedy rich people will constantly find new loopholes to avoid paying their fair share of tax," she said. Liam Byrne, chair of the business select committee, said HMRC must take a second look at the transaction. Siobhain Mc Donagh, a Labour member of the Treasury select committee, said the Treasury should "immediately step in to close this loophole."

Setiya declined to comment. One person close to him said the properties were available collectively and the single transaction was not structured to minimise stamp duty. Quadrature Capital donated £4mn to the Labour Party before the 2024 general election. The five flats were unlikely to exceed 1% of the house price, according to Tax Policy Associates.