It was not clear when or for how long the Marshals Service lost track of them.

CNN: U.S. lost track of two with known or suspected terror ties

The Norwich-born racer got out of the car aided by marshals before going to the track's medical centre.

BBC: SPORT | Motorsport | Formula One | Crash forces Firman out

After his short-lived debut at Bahrain, Karun Chandhok's Hispania had to be pushed back to the pit lane by the marshals after a suspected gearbox failure left it stranded on the track.

BBC: Lewis Hamilton fastest in Friday Australian GP practice