The crook burst into the BP garage on London Road in Clacton, Essex, with the elastic of the white pants pulled over his face and his eyes peering through the leg hole Photo: ESSEX POLICE

The man, who was armed with a carving knife, robbed the garage in Clacton, Essex, at about 11pm on Tuesday.

The crook burst into the BP garage on London Road in Clacton, Essex, with the elastic of the white pants pulled over his face and his eyes peering through the leg holes.

He grabbed the cashier in a headlock, pointed the serrated knife at his back and forced him to open the till before escaping with a three-figure sum in banknotes.

Detective Sergeant Kevin Cooper of Essex police appealed for any witnesses to the raid at around 10.50pm on Tuesday to come forward.

He said: "This was a nasty incident in which the robber used force and threatened the cashier with a knife. The cashier was unharmed but obviously badly shaken.

"We want to hear from anyone with information about the robber or may have seen him lurking in the area before the attack or saw him running away."

The suspect is described as a white man in his early 20s, six feet tall of medium build, and wearing a black Adidas tracksuit with three white stripes and dark coloured trainers.

"This was a nasty incident in which the robber used force and threatened the cashier with a knife. The cashier was unharmed but obviously badly shaken."