SIX people have been quizzed by detectives after a post box exploded, firing debris across a busy street and shattering windows.

Police were called out to Skipton Road, Colne, immediately after the blast at 10pm on Monday, but all that remained of the postbox was the base.

Detective Sergeant Steve Pemberton, of Burnley CID, said officers were treating the incident very seriously.

He said: "Somebody would have been seriously injured if they had have been passing at the time.

"Debris was fired over 20 yards and the post box was made of wrought iron and extremely heavy.

"It smashed the post office window and could have been extremely dangerous."

Six people were arrested and questioned by police yesterday. They have now all been released on bail pending enquiries.

Det Sgt Pemberton said there was still a lot of work to do, including forensic analysis, to establish the exact chain of events that had led to the blast.

Sub postmaster David Thornton, who lives above the office he has been running for 10 years, said the first he knew of the damage was when police arrived.

He said: "I heard a bang and it was very loud but I didn't associate it with my own place.

"When I went to bed I saw something had dropped onto the ground outside and then I noticed all the police lights flashing.

"It was only when I came downstairs to look through the shop window that I saw the damage.

"I was very angry when I realised what had happened. It could have been really dangerous."

Mr Thornton said that the whole of one side of the box had been blown through the shop window causing £500 worth of damage. The rest of the box landed in the road.

He said: "There is only the base of it left, which is about nine inches of metal sticking up. It was just a couple of feet away from the post office.

"There was some mail inside but it had been emptied at 6.15pm so there wasn't a lot damaged.

"The postbox will have to be replaced because there is nothing left to repair. It's caused a lot of hassle for me and could have been very dangerous."

Det Sgt Pemberton added: "Witnesses who are helping us with our inquiries but we would like to speak to anybody else who may have been in the area and coming out of Bargain Booze at the time."

Graham Moore, from Royal Mail, said: "People can still hand in their mail inside the post office during opening hours or the nearest post box is now in Keighley Road about 100 yards away.

"If people are concerned that they posted mail in the box between the last delivery and the time of the explosion they can call the customer service number on 08457 740740."

Witnesses are being urged to call Nelson CID on 01282 472645 or Crimestoppers on 0800 555 111.