Detectives are appealing for information after an attempted robbery yesterday which saw a shop assistant threatened with a knife.

The incident took place at around 5.40pm at Grange Stores in Dawnay Avenue, King's Lynn when a male entered the store and demanded money from the cashier while threatening him with a knife.

The cashier initially questioned the offender and asked him to remove the mask. When the offender refused the victim said he would call the police and the male fled empty handed.

He left the area on a BMX bike heading in the direction of Peppers Green.

He is being described as white, of slim build and between 5ft 5ins to 5ft 7ins tall. He was wearing a white skeleton mask, a blue anorak with the hood up, jeans and white trainers.

Police have said the mask was very distinctive and officers are keen to speak to anyone who may have spotted a male matching such a description in the area or who may have information relating to the incident or the mask.

Witnesses are asked to contact Det Con Gail Morley at Norfolk Constabulary on 101 or Crimestoppers anonymously on 0800 555 111.