The driver was seen leaving the Sobell Sports Centre in Islington, north London, on 10 July during an LU surveillance operation.

BBC: NEWS | UK | England | London | Tube sacking decision is deferred

He said that the latest information had come at the end of an "evolution" in his thinking though, which prepared him for Sobell's confession.

BBC: Today

Before you go getting any bad ideas, know that Benninger and Sobell haven't released the app for public use, and warned both transit systems in late 2011 (though neither region has fixed the exploit, the duo claim).

ENGADGET: Security researchers identify transit system exploit in San Fran and New Jersey, create app to prove it