His brief is to champion TfL's proposals to update the capital's transport system to parliamentarians, local authorities and pressure groups. London's triumph in the competition to stage the 2012 Olympics has given renewed urgency to projects such as the extension of the East London Line and the Docklands Light Railway.
Walkington, who joins next month and will report to MD of comms Ben Plowden, said: 'This is a profound moment to be joining TfL. Recent events have tested London and its public transport system.'
He added that he would have been 'less likely' to have accepted the job if London 2012 had failed.
Walkington joined BT in 1992 from Texaco and was director of public affairs for the telecoms giant from 2000 until January 2005, when he left to spearhead the Lib Dems' election push, resulting in 11 extra MPs. Bill Hamilton left TfL as head of PA at the start of the year, resurfacing at the Nuclear Decommissioning Agency.