A shop assistant was threatened with a knife when she refused to serve a man vodka on Sunday morning.
The shop assistant was threatened with a five-inch blade
The man asked for two bottles of vodka at Lynns Convenience Store on Summergangs Road, Hull, at 0815 GMT.
When the assistant refused to serve him because of licensing laws, he pulled out a five-inch blade and threatened her before stealing the vodka.
Humberside Police issued CCTV footage of a suspect and appealed for anyone with information to come forward.
The robber is described as white, aged 30-35, 5ft 11in tall, of medium build with short hair and a red circular mark on the right side of his face.
The shop assistant was not injured during the incident.