Managing director of London Underground Tim O'Toole resigns.

(From Guardian Unlimited)

The administration of the London mayor, Boris Johnson, has been dealt a blow with the resignation of one of its most highly rated executives.

Tim O'Toole, described as the capital's best public servant, has resigned as managing director of the London Underground, according to well-informed sources.

A US citizen who was awarded an honorary CBE for his organisation's response to the July 7 attacks, the reasons for his resignation were not clear last night, but it has been an open secret within City Hall that the Underground boss is keen to move back to the United States with his family.

However, the former freight …