AN armed robber attacked a female shop assistant before making off with £400 in cash.

The incident was at the Spar shop, in Whalley Road, Sabden, at around midnight last night.

Insp John O'Reilly said the man waited for the woman to turn her back before attacking her.

He said: "She suffered a nasty injury on her back after being attacked from the rear."

The woman required hospital treatment, but her injuries are not said to be serious.

He added: "At first she thought she had been stabbed with a pen, but her injuries are consistent with those that would be inflicted with a blade."