Former justice secretary Jack Straw, his current Scottish counterpart Kenny MacAskill and BP chief executive Tony Hayward have been invited to appear before a US hearing on the Lockerbie bomber's release from prison. They have been requested to attend the US Senate Foreign Relations Committee meeting on July 29. The ex-foreign secretary said he would have to consult the Foreign Office and former prime minister Gordon Brown before agreeing to discuss in person the circumstances surrounding the release of the Lockerbie bomber last year. US senators want to investigate the suspicions of some that oil giant BP may have had a hand in the affair. It was reported Tony Blair had been asked to appear but the claim has been denied by the committee. Cancer-stricken Abdelbaset al-Megrahi was released from Greenock jail on August 20 last year, having been given three months to live, but is still alive and with his family in the Libyan capital Tripoli. The controversy over his release flared up during Prime Minister David Cameron's first visit to Washington this week. Committee chairman Senator John Kerry said it needed to establish what led to the "mistaken" release of the only person convicted of the 1988 atrocity in which 270 people, including 189 US citizens, died.