THE BRITISH army last night began an investigation into how video tapes showing soldiers on anti terrorist training came to be sold at a car boot sale.
Experts said the tapes could have put soldiers' lives at risk and revealed highly sensitive operational information.
The Labour Party called for an inquiry, with the shadow defence minister, Mr David Clark, condemning the security lapse as incompetence bordering on treachery".
The films were bought by a man in a job lot of electronic equipment and tapes at a boot sale in Coventry, BBC TV's Nine O'Clock News reported. When he realised what they were, he handed them to the BBC.
The tapes show soldiers on military exercises at the main army training station in Northern Ireland, said the programme. They were handed over to the Ministry of Defence just before the Nine O'Clock News went on the air.
A ministry spokesman said it could not comment on the contents until it had studied them. "We welcome the receipt of the tapes from the BBC and we will investigate the matter," he said.
A BBC journalist, Duncan Kennedy, said the tapes contained alarmingly detailed information about soldiers' tactics. "It's about two hours of material, there are dozens of different exercises with varied scenarios how to combat snipers, explosive devices, how to handle public order, how to handle joyriders, rules of engagement in terms of when you can and can't fire.
"The video goes into a lot of detail. There is also a commentary voice over and it shows the officers in debriefing afterwards saying where they went wrong and what they did right."
He added: "There's lots of detail in the commentary that's of tactical operational importance, according to experts, which might be useful to terrorists.
"The IRA might have suspicions about something. This tape would confirm it all and enable them to come up with countermeasures to avoid detection and know how the soldiers are going to react in any given situation."
A counter terrorism expert, Col Mike Dewar, said he was "staggered" by the reported lapse, which he said could put soldiers' lives at risk. He was particularly concerned about material on electronic counter measures.
He said: "If the IRA got hold of this sort of film it would give them a clear insight into British tactics and capabilities, the sort of detail in my belief they have not had before."