A man entered the One Stop Convenience Store in Reffley Lane, at around 6am on Monday, December 3, and threatened a female member of staff with a knife.

He forced her to open the safe before making off with cash.

The terrifying robbery is the fourth to take place in the area in as many weeks. On Wednesday, November 21, a female shop assistant was threatened at gun point during an armed robbery at the Spar store and Post Office in Castle Acre.

Four men, one armed with a shotgun, are thought to have got away with around £3,000 in cash and cigarettes after clearing the shelves and raiding the till.

A second robbery was reported just a day later in Sutton Bridge when three men struck at Railway Stores, in Bridge Street. The men, one believed to be carrying a shotgun, stole cash from the till and took cigarettes from the shelves.

And – in the third robbery in the space of six days – a female shop worker in Mundford was threatened by three men brandishing thick pieces of wood on Tuesday, November 27.

She was forced to lock the front door as three men entered the Mace shop, on St Leonard's Street, and again stole cash and cigarettes.

The Reffley Lane robber is described as white, aged between 30 and 40-years-old and wearing a black balaclava and blue sports zip-up coat.

Anyone with information about the robbery is asked to contact PC Chris Parnham at Lynn Police on 0845 456 4567, or call Crimestoppers anonymously on 0800 555111.

Police are not linking the robberies at this time.

The Lynn News was only made aware of the latest robbery this week.