A MASKED robber held a gun to a bank cashier's head and demanded money before fleeing with cash.

Customers inside the HSBC in Broadstone heard the robber demanding £40,000 as he pointed the gun at the woman employee and she handed over money before the man fled, waving the gun at staff as he left.

The armed man was chased down the road by a have-a-go-hero, believed to be an off-duty policeman, before fleeing the scene in a car.

The police helicopter was scrambled as officers tried to track him down and an armed siege took place after they surrounded a block of flats in Commercial Road, Poole.Christine Gower, from Upton, was among five customers and three staff in the bank in Lower Blandford Road when the gunman entered.

Christine, 66, said: “This chap, dressed in black from top to toe, came in screaming that he wanted money.

“He had a gun in his hand and started shouting for money.

The woman in the booth was made to come out and he held the gun to her head.“They told him there wasn't much cash as it was early and they hadn't been open long.

“She got some money but he said it wasn't enough and demanded more.“ She got more and he went off.

”The man was described as wearing a scarf or balaclava over his face.

Andrew Smallpeice, owner of the Broadstone Cobbler next-door, walked out from behind his counter and looked through the bank window when he saw the masked man enter with a carrier bag.

He said: “I could see the guy with a gun pointed at the staff - it looked like a handgun, possibly a pistol.

“I watched as the robber backed out of the bank, still pointing the gun at the staff.

“He ran out and across the road and all the traffic came to a stop.

“Then I heard someone shouting and a man was chasing him.

”Claire Cormack, at Oakley Village Butchers opposite, saw the robber crossing the road towards her.

“I just looked at my boss and said 'oh my god there's a robber',” she added.

Claire said an off-duty policeman stood in front of the butchers and screamed “stay where you are” at the robber and continued to chase him despite having the gun pointed at him, too.

Onlooker Penny Jarvis followed them down Clarendon Road and West Way, where the policeman was seen kicking the car as the robber fled.

Penny said: “I ran after them as I was worried about what would happen to the policeman if the robber shot at him.“He didn't and I caught up with him in West Way, just in time to see a red car go speeding off up Upton Way.”n