So when intelligence came in giving the location of a suspected DMP, immediate action had to be taken. The PM was consulted and asked for permission to 'stand to' the SAS counter-terrorist team from their base in Hereford. He gave the go-ahead.

The members of a thirty-minute team have to be able to reach camp within half an hour of being paged. As soon as the messages came through, just like volunteer firemen, they stopped whatever they were doing and got on the road.

At the same time a Chinook helicopter took off from its RAF base to pick up the team. By the time the guys had arrived at the camp and come into the crew room, where their gear was packed and waiting, the commanders were already writing down instructions on white marker boards.

The most important piece of information about the job appeared in big red capital letters: HELI PICK-UP COVERT OP UK

The team knew instantly that it was a civvies clothes job, in boots and jeans, and that once the job was done, it would never exist on any database; they would act as if it had never happened.

Within thirty minutes the team, along with two Range Rovers, was airborne in the Chinook. Each member was armed with an MP5-SD, the suppressed version of the machine gun, and wore earphones and a mic so that their commander could relay orders for the attack as they flew north.

The Chinook landed three miles from the target area, on a desolate stretch of mudflats downstream. The wagons were swiftly unloaded, and within minutes the team was on its way to an area of abandoned warehouses and dockyards.

The whole operation to get the team to the target had taken less than four hours, and now three of the four groups were ready to attack, with sniper one keeping the commentary going.

'Sierra One has Red One, Two and Three ready.'

Red Four was taking the entry point furthest from their start position; slowly they crawled under the final window to reach the fire-escape door where they were going to make entry.