The 54-year-old victim had just crossed The Dana footbridge over the railway line at around 10.45am today when he was approached from behind in Victoria Street.

A youth aged about 16, grabbed a blue canvas bag the man was carrying and then punched him in the face when he refused to let go, causing a slight cut to his eyebrow.

Police Constable Lee Grantham, the investigating officer, said the victim had been shopping in the town centre.

“The youth struck him with a single punch and then ran off towards the river bank with his bag containing a bank card, woolly hat and gloves.

“We are appealing for anyone who saw this incident, or possibly the youth following the man between about 10.35 and 10.50am, to contact the town centre police station on 101. Information about the identity of the offender can also be given to the anonymous Crimestoppers charity on 0800 555 111 or via its website www.crimestoppers-uk.org.”

The youth had short black hair brushed forward as if gelled and was wearing a black hooded bomber-style jacket zipped at the front with black trousers and trainers or pumps.