Tube chief steps down to return home to America

The head of London's Tube network has quit, it emerged last night. London Underground's managing director, Tim O'Toole, stepped down to return to his home in the United States, Transport for London said.

The 53-year-old, who was awarded an honorary CBE for his organisation's response to the 7/7 terrorist bombings in 2005, is leaving after six years. He will officially step down at the end of April.

He said: "I am sad to leave London Underground but after six years in London it is time to go home. I shall always be grateful for the privilege of being part of such a great institution." Last month he told MPs that the Underground would always be a target for terrorists because of its "iconic" status, but said he felt the current threat would eventually "burn itself out".

The Mayor of London Boris Johnson, who will now have to seek a replacement, paid tribute to Mr O'Toole, saying he had "led from the front".