A PLANNED prison break-out may have been foiled by three young boys after they found a sawn-off shotgun in woodland yards from where some of Britain's most feared prisoners are detained.

The youngsters were gathering twigs for a tree-house when they found the weapon and about 20 shotgun shells and two black balaclavas in a blood-spattered sports bag, near Frankland Prison, Durham.

The prison houses about 700 of the country's most dangerous criminals, including al Qaida bombers Omar Khyam and Dhiren Barot.

A Prison Service source told The Northern Echo last night: "The gun was probably planted there, possibly for a break-out."

Ten-year-olds Josh Renwick and John Peace, and Elliott Stewart, 11, found the weapon in undergrowth near the road leading to the prison, at about 12.20pm yesterday.

John picked up the bag and the boys took it to Elliott's house, in Beech Close, from where his mother called the police.

An armed response unit immediately sealed off the woods, while forensic investigators and officers with dogs searched the area for evidence.

They also took the weapon away for tests.

Duty Sergeant David Coxon, who was at the scene for Durham Police, said: "Armed officers were used to ensure the safety of the public. There was no specific threat."

Asked whether the weapon was linked to the prison, Sgt Coxon said: "We are keeping an open mind as to where the gun has come from."

A force spokesman said: "A detailed search was carried out in the area, which drew a blank.

"The weapon will now undergo forensic testing to see if it has been used in crime."

The shotgun was found near a path in dense woodland paved with ivy, leading from a track to Low Newton Farm.

Elliot's mother, Treena Stewart, said: "John brought the bag out into the street. I thought the lads were just messing on and then I thought, crikey, they're telling the truth. It was a real shock.

"It's frightening to think that that turned up on our doorstep. It's given us all a bit of a jump.

"I wonder whether someone was going to come back for it.

"We don't expect that kind of thing here. It's usually very quiet. We've never had any bother."

Lynn Renwick, the mother of Josh, learned of the find when she returned home for lunch.

She said: "I'm just very glad it's been found. I couldn't believe it. I couldn't go back to work. I wanted to be here if the police were going to interview the boys.

"Everyone uses the footpath where they found the gun as a shortcut, so it can't have been there very long. It normally feels very safe here, but I don't like them going into the woods and I don't think they'll be allowed to build dens for the time being."

Frankland Prison has seen several high-profile safety incidents in recent months.

A Prison Service spokesman said because the gun was found outside the grounds of Frankland, the matter will be dealt with by the police.

Police are appealing for anyone with information about the gun to call 0845-60-60-365.