DETECTIVES hunting a gang of machette-wielding bank raiders today appealed for residents who saw the robbers switch cars to come forward.

Officers investigating the attempted raid on the NatWest, Copy Nook, Blackburn, believe that information could hold the key to catching the gang.

And while detectives are keeping an open mind about where the raiders are from, one line of inquiry is that they were travelling criminals from outside of East Lancashire.

Four balaclava-clad men burst into the bank at 3pm on Thursday after using a beer barrel to smash a side window.

Minutes earlier a security van had delivered cash.

Customers screamed and some tried to flee the bank as the raiders entered brandishing machetes and crowbars.

But the gang said "it's alright, you're going to be alright", a move which witnesses said calmed people down.

Moments later the raiders fled empty-handed after failing to force their way into the rear of the bank.

They drove off in a champagne-coloured Saab convertible up nearby Lambeth Street.

Today it was revealed that the car has been recovered in an alley near Walter Street, off Audley Range, where police believe they switched into another vehicle.

Detective Sergeant Paul Ryan, of Blackburn CID, said he was keen to speak to anyone from that area who saw the vehicle the four men switched into.

And he added: "We are also not taking for granted that we have spoken to everyone who was in the bank at the time, so we would like to speak to anyone who can come forward with information to help us."

A spokesman for NatWest would only comment to say that staff were "liaising" with police over the raid.

Anyone with information should call Blackburn CID on 01254 353569 or Crimestoppers on 0800 555 111.