Police are appealing for witnesses following a robbery at a bookmakers in Stevenage. At around 9.45pm last night an offender approached William Hill in The Hyde whilst a member of staff was locking up. He threatened her with what is believed to be a gun before taking around £1,500 in cash. The member of staff was not injured during the incident. The offender left the store by the back door towards Randalls Hill. He is described as being approximately 6ft tall and of slim build. He was wearing a black crash helmet covering his face, black jacket, black trousers and trainers.