POLICE have released more information about the theft of a cash box from a security guard as he made a delivery to a Tesco store in High Wycombe yesterday.

The security guard was making a delivery to the Tesco Express store in Amersham Road at about 1pm when a silver BMW convertible with a black roof, registration YY07 XFF, pulled up behind and blocked the van in.

The balaclava-clad passenger got out of the car and approached the security guard, who was carrying the cash box, in an intimating fashion, police say.

As the man approached, the guard put the cash box on the ground. The man picked it up and got back in the BMW which drove off towards Amersham.

Police scrambled a helicopter to trace the vehicle. The security guard was not injured in the incident.

The driver of the car is described as Asian with light coloured skin, he has very short dark hair, dark stubble, aged in his thirties and is well built.

The passenger is thought to be around 6ft 2ins to 6ft 3ins and slim. It is thought that there could have been a third person in the back of the car.

Police believe the robbery may be linked to an incident in Ford Street, in which residents reported a loud bang and say men on a driveway wearing balaclavas.

Investigating Officer, Det Con Richard Hobson, said: “There were a few people around at this time of the day who might have seen this happen and I am keen to hear from anyone with information.

“At about 1.10pm we have had reports that residents in Ford Street, Wycombe Marsh, heard a loud bang and saw men on a driveway wearing balaclavas.

“One is described to be white and the second to be mixed race.

“When the males were challenged they put something into the rear of a silver 6 series convertible BMW and drove off.

“It is possible that these incidents might be linked and the offenders, or the vehicle, which I believe has false registration plates, might have been in the area before the robbery happened.

“I am asking anyone who has any information, no matter how insignificant they believe it to be, to get in touch.

“Fortunately the security guard wasn’t injured by the robbery but has been left distressed and shaken.

“I would like to reassure residents that there is a team of detectives working on this investigation to ensure that we catch whoever is responsible and I urge anyone who might have been in the area and seen any suspicious activity, to contact the police immediately.”

Contact police on 0845 8 505 505 or the Crimestoppers charity on 0800 555 111.