Bomb disposal specialists were called to a Norfolk motocross circuit this morning after a second world war mortar was discovered.

The rusty projectile was unearthed as grounds staff cleared the track at Cadders Hill in Lyng, near Dereham, in preparation for a championship race meeting.

Norfolk police were contacted at about 9am following reports that an unexploded world war two device had been discovered.

A bomb disposal squad from Colchester was subsequently called into action, setting up a 200m safety perimeter around the object.

But a series of precautionary x-rays soon confirmed that there was no danger, with the discovery believed to be a practice mortar bomb, filled with cement. The dud mortar was then removed from the site.

Phil Armes is PR officer for the Norwich Vikings Motorcycle Club which is based at the circuit.

He said: 'The mortar was found on the circuit while they were working on the track using an excavator.

'They think it was possibly used by the Home Guard when they were training here during the war.

'It was an amazing find, but the x-rays showed it was never explosive. Actually, the bomb disposal guy came back with it over his shoulder before they took it away.'

A police spokesman said no properties needed to be evacuated as the bomb was discovered on open ground.

The circuit was being prepared for the third round of the Maxxis British Motocross Championship, which is due to bring some of the world's best riders to Cadders Hill on April 17.