Chelsea have held an internal investigation after a seven-inch knife was discovered in a Chelsea dressing room by cleaning staff.

The Daily Mail says the blade was found in the changing area used by the club's youth teams, who share the training-ground complex at Cobham with first-team stars such as Frank Lampard, Fernando Torres and John Terry.

One source at Chelsea's academy said: "The knife looked liked something out of a Rambo film."

The youngsters, all under the age of 18, were called into a meeting after the weapon was found, warned about the potential consequences of knife crime and given the opportunity to come forward. No-one did and the club later decided to take no further action.

At the time, some members of staff were so concerned by the discovery that they wanted to call in the police to take fingerprints.

But the club claimed that the knife was left by a contractor doing work in the youth-team dressing rooms during the players' two-day break. They intend to track the contractor down and return it to them as soon as possible.

A Chelsea spokesman said: "A knife was found on the premises at a time when only cleaning and building contractors had been on site. The club has determined that it did not belong to any player or staff member as the area was sealed off and we are satisfied it is not a matter of concern. The matter is closed."