ARMED robbers made off with up to £80,000 after holding up a security guard in a terrifying daylight raid in Trowbridge on Monday.

Two masked men, one brandishing a handgun, held up a guard delivering money to cash machines at the Tesco store in County Way.

Detective Inspector Deborah Waters of Wiltshire Police is leading the inquiry into the raid and believes it was a professional hit.

She said: "It is a very unusual sort of crime, especially for this area. I would certainly say it was well planned. It would appear they knew the time of the drop-off of the cash, they planned their escape route and they had a vehicle waiting."

Detectives are already liaising with other forces across the south west and beyond to find out if the pair, who are not thought to be local, could be linked to other serious crimes.

The raid happened just after 3pm in full view of people shopping at the busy supermarket.

Witnesses saw the Group 4 security van pull up in font of the store's ATM machines, followed by an Interlink Express transit van, which had false numberplates.

One of the security guards got out of the van and walked to the building that houses the cash machines when he was approached by the robbers, one carrying a gun now known to be a replica, who demanded he hand over the money.

The robbers got away with containers of cash and, abandoning the van ran off over the footbridge leading to Clarendon Avenue.

A member of the public gave chase and the men were then seen to split up and to remove the balaclavas covering their faces.

It is thought they then got into a silver car, probably an Audi, parked on West Ashton Road.

A spokesman for Tesco said: "We confirm there was an incident at the store and thankfully no staff or customers were hurt."

The exact amount of cash stolen has not been confirmed but police said it runs into tens of thousands of pounds, made up of £20 and £10 notes contained in dispensing cassettes marked Royal Bank of Scotland.

A huge police operation was launched immediately following the incident, the police helicopter was called in and 30 officers are involved in the inquiry, which has included a painstaking search of the surrounding area.

The men are described as white, about 5ft 10ins tall, of stocky build, both wearing all black clothing with white trainers.

Police are appealing for anyone who was at the store at the time, anyone who saw the Interlink van following the security van, anyone who saw the two men running away from the store and anyone who spotted the silver car at West Ashton Road to come forward.

Anyone with any information can call Wiltshire police on 0845 4087000 or Crimestoppers anonymously on 0800 555111.