POLICE have only just discovered that they held the fingerprints of the ringleader of the July 7 bombings on file before the attacks, it was revealed today.

West Yorkshire Police said it "recently" found two sets of Mohammad Sidique Khan's prints in its archives - one of which dates from when he was arrested aged just 11.

The force has launched an inquiry into the records as it prepares for the upcoming inquests for those killed in the 2005 London atrocities.

West Yorkshire Police took Khan's prints for the first time when he was arrested in April 1986, aged 11, for being involved in receiving stolen goods.

The second set of prints was taken by the force in February 1993, when Khan was arrested for assault.

The records came to light after Scotland Yard contacted West Yorkshire Police last month to check whether they had the July 7 bomber's fingerprints on file.

Details of the discovery emerged at a hearing at the Royal Courts of Justice in London to decide what form the inquests should take.

Khan, 30, from Dewsbury, near Leeds, killed himself and six innocent people when he set off a bomb on a Circle Line Tube train at Edgware Road on July 7 2005.

Three suicide bombers under his command, including Jermaine Lindsay from Rawthorpe, murdered another 46 travellers in separate attacks that day on two other London Underground trains and a bus.

West Yorkshire Police said in a statement: "In preparation for the inquests into the events of July 7 2005, West Yorkshire Police recently found two sets of fingerprints in its archives belonging to Mohammad Sidique Khan, of which it was previously unaware.

Max Hill QC, counsel for the Metropolitan Police, stressed that this was not the first time that Scotland Yard asked West Yorkshire Police for detailed information about Khan.