DETECTIVES have released this CCTV picture of a robber brandishing a knife at a shop assistant in Basingstoke.

They believe the man has targeted three shops in the town within eight days.

Officers have stepped up patrols and encouraged shopkeepers to pay more attention to security measures in the hope of both foiling and tracing the attacker.

The first robbery took place at about 6.30pm on Wednesday, November 15, at Kempshott Post Office and Store in Pack Lane. The man threatened the cashier with a meat cleaver and told her to put money into a plastic bag. He made off with about £600.

On Tuesday, November 21, the man entered the Co-op in Buckskin at about 10.50pm brandishing two large kitchen knives. As shown on the CCTV image, he threatened the woman working behind the till and made off with about £150.

The most recent attack occurred just before 9pm a day later at The Local off-licence at the Kings Furlong Centre.

Again, the man produced two large knives, one of which was a meat cleaver, and threatened a man and woman in the shop.

He told the man: "Don't try anything or I will cut you up."

The robber, who remained chillingly calm, said he was not afraid to use the knife. He took £150 in the raid.

Detectives describe the man as white, in his late teens to early 20s and about 6ft. He has been wearing a black waist-length parka jacket with a hood with a brown fur trim and blue stonewashed jeans which have a number of rips. He also wears a black woollen scarf, which he uses to hide his face, and a pair of black gloves.

Police are urging anyone who sees this man not to approach him, but to dial 999 immediately.

Detective Constable Sion Margrie, of Basingstoke CID, said: "It is important to remember that it is not only the shop that is the victim of this type of crime.

"These innocent people are simply doing their job and do not deserve to be threatened in this way. Fortunately, they have not been hurt, but the victims have been left extremely distressed by what happened to them."

Anyone with any information is asked to contact Det Con Margrie, at Basingstoke CID, on 0845 045 4545.