Glasgow The thirty-minute team made the best use of the shadows as they approached their entry points and prepared for the attack. Close by on the river Clyde, two tugs passed in opposite directions, their stubby bows pushing through the inky-black water.

The four snipers were giving cover with their 7.62mm suppressed longs from fire positions 200 metres from the target building, a single-storey warehouse. They watched all sides and the roof, ready to give warning instantly if they saw movement from within the target that would compromise the assault team as they made their entry.

Sniper one could see all four entry points and the assault groups moving in on them. He was giving constant updates to the entire team and the team commander, who was at the rear of the target with his signaller. He was the link between the team, the heli and London.

'Sierra One has no change. No light, no movement'

Three of the four assault groups reached their entry points, and each MOE man carefully began attaching two 10?15cm pads of explosive to the doors by their adhesive undersides. The brick-sized rubber door-entry charges were stuck close to the door hinges inside the frame.

'Sierra One. No change.'

The calm, reassuring words gave the team confidence: everything was OK and someone had eyes on them as they continued with their work.

They couldn't afford to cock up. Bringing in special forces to take action against non-terrorist targets on UK soil is a big deal, and permission for such action can only come from the very highest level.

The terrifying extent of the Meltdown crisis, with its threat to national and international security, had been kept from all but a very few. The mission to seek out and destroy the drug factory was urgent but it had to remain totally secret.