A CCTV image has been released of a man in a mask who threatened terrified bank staff with a shotgun.
Police have obtained the image from Lloyds Bank on Market Street after two men walked in and threatened staff with a sawn-off shotgun and a knife on September 17 at 4.45pm.
They demanded money but left empty-handed before getting into a dark-coloured Volkswagen Golf parked on Frog Lane.
The first offender is described as being of large build, wore dark clothing and had a black balaclava over his face.
The second offender is described as being around 6ft tall, wore a navy blue hooded top and a mask over his face.
The bank is now offering a reward to anyone who provides information which leads to the arrest and conviction of those responsible.
Detective Constable Kath Andrews said: “It is a week since the incident and we are keen to trace those responsible.
“Nothing was stolen but, as you can see from the image released, staff were left terrified by the sight of a man in a mask holding a shotgun.
“The Lloyds Banking Group is a member of the British Bankers Association (BBA) Reward Scheme and as such may offer a reward of up to £25,000 to any member of the public who provides information which leads to the arrest and conviction of those responsible for this.
“If you have any information, no matter how insignificant you may think it is, please call us as it may help us find those who committed the crime.”
Anyone with information should call police on 0161 856 7124 or the independent charity Crimestoppers, anonymously, on 0800 555111.