A WOULD-BE robber attempted to steal a cash box from a security van outside Tesco in Highcliffe this afternoon.

A spokesman for Dorset Police said the force was called to the store in Lymington Road at 12.07pm, and an investigation has been launched.

A woman who was in the shop at the time said she heard a "commotion" while paying at the self-service checkout.

"I thought someone had knocked over a stack of tins," she said.

"Then I heard someone shout ‘get his number plate’.”

The woman, who asked not to be named, said she thought a guard from a security van parked outside of the store had been confronted by the offender.

“The guard came running into the shop carrying a money box. He looked as white as a sheet.

“One of the guys working behind the counter went running out of the shop to chase after the robber.”

A spokesman for Tesco said: "We are assisting the police in their investigation and are happy to report that the store is open for business and trading as normal."

Police are appealing for witnesses to get in touch by calling the 101 number.