The man withdrew a small amount of money for himself from a cashpoint on York Road at about 2100 BST on Friday.

But as he walked away the boys, all aged about 16, assaulted him, searched his pockets and forced him back to the cash machine to get more money.

A light blue private hire car stopped to help but the gang told the driver not to interfere and he drove off.

The victim suffered bruising to his head and back in the attack.

Police would like to speak to the taxi driver, his passenger and any other witnesses.