Some of Britain’s biggest companies have been urged to boycott Russia’s main annual business summit in St Petersburg next month, amid growing political tensions triggered by the poisoning of Sergei Skripal and his daughter.

Bob Dudley, BP’s chief executive; Ben van Beurden, the chief executive of Royal Dutch Shell; and a number of other UK executives attended the St Petersburg International Economic Forum last year.

The event, hosted by President Putin, is due to be held this year on May 24-26, three weeks before the country hosts the football World Cup.

Bill Browder, a fund manager who advised on investments in Russia and who campaigns against corruption there, said that it would be “highly unpatriotic” for any British company to attend the event, which has…