The man, wearing a balaclava, entered the Hemingford service station at about 10pm before demanding cash from the till. He was handed over some money and he ran off towards St Ives. He is described at white, 5ft 7in, medium build and wearing a black Adidas top, dark trousers and whit trainers. He was also wearing black leather gloves. No-one was injured in the incident. Detective Constable Kirsten Kitchen said: I would urge anyone who was in the area and saw anyone acting suspiciously, or where the man went following the robbery, to call police. INFORMATION: Anyone with any information should call DC Kitchen on 101 or Crimestoppers, anonymously, on 0800 555 111.