TWO armed robbers attacked a security van driver and sprayed petrol in his face before stealing thousands of pounds in cash.

The men, described by police as very dangerous, were armed with a cosh and struck outside Helmshore post office, in Broadway, shortly before 11am yesterday.

They approached a guard delivering cash, sprayed petrol in his face and stole three boxes containing a significant amount of cash.

A third man seen close to the scene is being sought by police, who believe he could be an accomplice of the two attackers, or a vital witness.

"These men should not be approached, they are very dangerous", DS Derek Jones said.

Twenty officers sealed the road off yesterday and made house-to-house inquiries, prompting several witnesses to come forward.

DS Jones added: "One of the two robbers struck the guard a number of times with a blunt instrument." The guard was treated at the scene by paramedics.

The first raider was white, in his early 20s, wearing dark clothing, with his collar pulled up to cover his neck and the lower part of his face.

He was wearing a blue or black top and a baseball cap with a small logo on the front.

His accomplice was also white, also wearing dark clothing and also with a collar pulled up to conceal the lower part of his face.

He was wearing a dark flat cap, back-to-front. A third man seen in the vicinity of the raid was in his late 30s, wearing light coloured clothing.

DS Jones added: "We cannot say for sure if he was associated with the crime but he may be a vital witness. Both offenders ran off in his direction."

"He must have had a good view of what was taking place and also of the offenders. This man has not been traced and has not come forward. It is vital that we speak with him."

Anyone with information should contact Rossendale Police on 01706 237242 or Crimestoppers on 0800 555 111.