A suspected violent criminal escaped when two masked accomplices armed with a shotgun ambushed his prison van.
Prisoner escapes in armed hold-up
Wayne Joseph Connor, 20, was driven away after being snatched as he was travelling to court from Feltham Young Offenders' Institution in west London.
Police said two men wearing balaclavas smashed the driver's window and threatened him with the gun at about 7.30am.
They demanded that the driver, who was accompanied by a second member of staff, release Connor from the rear of the six-cell van.
A Metropolitan Police spokesman said the driver required hospital treatment for cuts and bruises.
Police cordoned off several roads as they investigated the escape in Bedfont Road, near Bedfont Lake, in Feltham.
A Metropolitan Police spokeswoman said: "Connor was due to attend Woolwich Crown Court today (Monday) to stand trial for aggravated burglary and grievous bodily harm.
"If you know where Wayne Connor is, do not approach him - ring police immediately."
A spokesman for Serco, which is responsible for prisoner transfers, said the vehicle was travelling to Woolwich Crown Court.
He said the driver suffered minor injuries and the second staff member was unhurt. Two other prisoners on board were detained at the scene.