UK & World News
Hostage Rescue: Deadly Message To Militants
The "go-no-go" decision is never easy. When a Prime Minister orders British Special Forces into a hostage rescue, he knows that when he calls their headquarters in Regent's Park he is dialing up death.
At best the dead will only be among the kidnappers. At worst, as was seen in Nigeria earlier this year, the hostages are killed during the operation - perhaps some of the British "blades" may also die.
So the "go" order is given only when the hostage is in imminent mortal danger.
Helen Johnston and her three colleagues from Medair were increasingly drawing attention from greater and greater numbers of Taliban in the remote caves where they were being held in Badakshan, northern Afghanistan.
As David Cameron said, she was in danger and it was getting greater.
After Chris McManus, 28, was killed during the March rescue attempt in northern Nigeria, which was a joined British and Nigerian operation, and only a day after another German hostage was killed in the country, the Prime Minister took no chances.
Britain's most senior Special Forces officers took personal charge of the Badakshan raid.
Special Forces soldiers kept the kidnappers under close observation after what General Adrian Bradshaw, the deputy commander of coalition forces in Afghanistan, said was a gruelling hike through the mountains to arrive undetected.
It is likely they were able to pull this feat off by a High Altitude High Opening (HAHO) parachute jump from 30,000ft.
By using oxygen masks and specially-adapted parachute wings SAS and Special Boat Service (SBS) troopers are able to silently "sail" up to 30 miles onto a target without their enemies even hearing the engines of a distant aircraft.
British and American commandos have, as General Stanley McChrystal famously said, "been killing insurgents on an industrial scale" for several years in Afghanistan.
As a result their techniques for kill or capture operations of this kind are finely tuned.
Any discussion of their tactics outside the Special Forces communities centred around Hereford and Poole is strictly forbidden.
But it is known they no longer use conventional firearms. All of their operations, day or night, are conducted with silenced weapons.
So it is unlikely the kidnap gang, all of whom were killed during the raid, would have known they were under attack.
On this occasion the British-run operation conducted alongside American forces, was a success.
Mr Cameron said the operation showed that in future, kidnappers could expect a "swift and brutal end".
In doing so he revealed another typical tactic of a Special Forces operation - they tend not to take prisoners.