According to recently leaked documents seen by the Guardian and the Bureau of Investigative Journalism, representatives of big business rubbed shoulders with senior politicians at a ‘black and white’ ball in February. David Cameron and other top politicians dined with billionaire donors at a dinner costing £1,000 per head. Among the guests were executives of a highly controversial doorstep lending firm criticized for soliciting retired elderly people and who had donated more than £25,000 to the party in the past three years. The first donation came when the government was being encouraged to regulate payday loan companies. Property tycoons and a Ukrainian energy boss also attended the event. The leak comes following accusations that Mr Cameron backtracked on his pledge to clean up politics by getting rid of giant company lobbying. Last year a network of bankers, businesspeople and lobby groups attended a Conservative fundraising dinner costing £12,000 per person.