Royal Bank of Scotland (RBS) has apologised for misleading a parliamentary committee over its treatment of small businesses.The bank's chairman, Sir Philip Hampton, admitted evidence given by two executives was wrong, though he insisted the executive had made "a genuine mistake".Andrew Tyrie, the committee chairman of the Treasury Select Committee, said the executives had been "wilfully obtuse" when discussing the controversial Global Restructuring Group.Deputy chief executive Chris Sullivan and Derek Sach, head of the GRG unit, were summoned by the committee in June to discuss claims that it destroyed small firms for profit, but they denied the unit was a "profit centre"."The evidence the bank's representatives provided was not correct," he said in a letter to Tyrie on 22 August, made public on 23 November, adding that the men "did not intend to mislead".The debate over the lender's treatment of small and medium-sized businesses is the latest in a series of scandals RBS has found itself tangled into since it was bailed out by the government in the wake of the financial crisis.RBS shares were up 0.77% to 380.60p at 08:50 on Monday.