The raider struck at the BP filling station - taking money from the till - and from a workers pay packet.

After holding his jacket over his hand and pointing at a female sales assistant as if it were hiding a weapon, the thug demanded cash before walking behind the counter to steal £160 from the till.

He then told her to hand over more money and the woman gave him her own pay packet. As he searched for more items to steal he was disturbed by a member of the public who chased him from the shop.

Det Sgt Paddy Dowling, of Blackpool CID, said: "This was a cowardly attack on a lone female shop worker.

Police have been examining CCTV from the store since the robbery which happened just before 7pm on Monday.

The man police are looking for is described as white, around 5ft 10in tall, in his mid 20s and of a slim or wiry build.

He wore a grey sweatshirt pulled over his face, dark tracksuit bottoms and trainers.

The victim said he had a 1.5cm scar somewhere on his face.

Detectives have also spoken to the man who chased the robber off and have taken a statement.

Anyone who saw the robber, or has information about the incident, is urged to call Blackpool Police on (01253) 293933 or Crimestoppers on 0800 555111.