Defence chiefs drafted a "high-risk" top-secret plan to withdraw British troops from a key battleground during the Bosnian War, newly declassified documents reveal.
The air evacuation from Gorazde, involving 1,500 military personnel, was presented to Prime Minister Sir John Major in 1995.
The planned mission was proposed amid fears the Muslim enclave would fall under an offensive from the Bosnian Serb Army.
Details of the plan, codenamed Operation Screwdriver, disclosed how helicopters would be brought in, under the cover of relative darkness, to airlift British troops to safety.
The documents, released by the National Archives at the Kew show, said the operation would last "10 to 15 minutes".
However, the proposed mission was not without its risks.
According to briefing notes, the operation would have involved a fleet of 30 helicopters, as well as Harrier jets, all on standby in nearby Italy.
A copy of a letter from the then Defence Secretary Michael Portillo to the prime minister in July 1995, said: "We must never lose sight of the fact that this is a high-risk operation in military terms."
The classified note said the operation would require "tactical surprise" to be effective, as well as a green-light from United Nations commanders.
"It is planned that some disruption measures will be employed immediately prior to the evacuation sortie," the message read.
"These would range from the precise electronic jamming of 'enemy' communications through to the destruction of any key installations positing a threat to extraction."
However, the prime minister was not impressed with the plan.
"Not at all on," Sir John replied, in a handwritten message to the Operation Screwdriver contingency plan briefing document.
"Cock-up factor clearly present."
Gorazde was one of several designated UN "safe areas" besieged by Bosnian Serbs.
More than 25,000 UN troops were deployed to Bosnia between 1992 and 1995.
Cover Image: 1st Battalion The Royal Welsh Fusiliers, who had been held hostage in Bosnia, disembarking from a Canadian aircraft in June 1995 (Picture: PA).