A CCTV appeal has been launched after a man wielding a large knife robbed a shop in Coldharbour Lane, Hayes .
Police have released footage showing a suspect in their robbery investigation, who had his face covered with a striped scarf.
A man waited for another customer to leave the store before he approached the staff, brandishing a large knife.
He stole the cash and then made off down Coldharbour Lane before turning left into Minet Drive.
The suspect seen in the footage was wearing a black hooded jacket and "distinctive" green trousers.