A reward of £5,000 was offered last night to catch a "Michael Caine" lookalike who threatened to shoot Post Office customers.

The Post Office will pay the money for information leading to the arrest and conviction of the raider who stole more than £10,000 in euros from the Ship Street branch in Brighton on Monday, November 28.

The gunman, wearing Michael Caine-style thickrimmed glasses, threatened to shoot a Post Office delivery man as he arrived with a cash bag at 12.45pm.

The offender grabbed the bag and the two struggled until the offender produced the gun.

The weapon was pointed and waved at the victim, other members of staff and customers.

He shouted he would shoot unless the delivery man handed over the money.

The Post Office employee gave up the struggle to save members of the public and himself and the gunman fled with the money bag.

The offender ran out of the post office towards North Street and then in an unknown direction.

The delivery man, in his 40s, was uninjured but was badly shaken by his ordeal.

Sergeant Steve French, leading the investigation, said: "We have had an excellent response so far from members of the public and we are actively pursuing some new lines of inquiry.

"This was a terrifying ordeal and we need to catch this man before he strikes again.

"Did you see him before the robbery, perhaps acting nervously? Did you see him in the days leading up to the robbery, hanging around the post office and thought his activity was suspicious?

Did you see him running away from the scene?

"I would also like to directly appeal to banks, money exchange outlets and bureaux de changes to be on the look out for large transactions taking place."

The gunman is white, 25 to 30, slim and 5ft 8ins with pointed features, a stubbly face and was wearing dark, heavy rimmed glasses, which may have been worn to disguise part of his face.

He wore a grey-blue woollen beanie hat.

Witnesses or anyone with information should contact Brighton CID on 0845 6070999.