A masked robber waved a pistol in a security guard's face and shouted: "Hand over the money or I'll shoot you."

The gunman pounced on the Group 4 Securicor worker as he delivered cash to the Nationwide building society in Church Road, Hove.

He cornered the security guard in the doorway of the building while the guard's colleague waited in their van.

The hooded gunman then grabbed the cashbox and ran off in the direction of Brighton. Police are unsure whether a getaway car was waiting.

Tonight police were trawling through CCTV footage recorded in the area to see if it identifies the gunman, who escaped with thousands of pounds.

Witnesses told of their shock after they were caught up in the aftermath of the raid at 9.10pm on Monday.

Builder Barry Philips, 42, of Church Road, said: "I didn't see the actual robbery but I heard shouting.

"I looked out of my window to see what was happening on the street below and saw a man with his head covered running away. The weather was awful and I can't imagine he stayed on foot for long."

Police spent yesterday interviewing residents and witnesses as well as looking at surveillance footage from businesses in Church Road.

Alan Mulholland, the owner of Mulholland's off-licence yards from the bank, said: "I saw the security van pull up and minutes later a police car came tearing down the road."

"I didn't put two and two together until an officer came to ask me about it and checked if we had any video footage."

In March last year, two knife-men escaped on the back of a motorbike after robbing three cash boxes from Securicor guards at the branch.

During the struggle to steal the money, one cash box burst and dozens of people ran to grab fistfuls of £20 notes.

Mido Samy, the manager of St Aubyn's newsagents in Church Road, said: "The police came round and asked me for my CCTV videos."

A Securicor spokesman said: "Neither of our couriers was injured."

Police described the robber as white and aged 20 to 30. He was wearing a green scarf over his face, dark jeans and a navy blue or black jacket with the hood up. Witnesses should call Detective Seargeant David Osland at Brighton and Hove CID on 0845 6070999.