Fergus held his AK in his right hand and the curved, thirty-round magazine in the left. He checked the top of the mag to make sure the shiny brass rounds were seated correctly before placing it in the assault rifle's mag housing and listening for the reassuring click as it locked into position. Then he gave the mag a quick shake to make sure it was fully home.

'Now you,' he said to the sweat-drenched guerrillas. 'Just do what I did.'

Fergus could load, unload and strip down a weapon with his eyes closed – he had done, thousands of times – but now he kept his eyes on the twelve young men as they copied his actions. Young men? They were kids, most of them not yet twenty and the youngest maybe seventeen.

Most were dressed in ripped jeans and old Brazil or Man U football shirts. Some had thin, wispy beards. It was as though they were trying to prove they really were man enough, mean enough and brave enough to be FARC guerrillas. The younger boys were smooth-faced; they probably hadn't even started to shave.

Their faces were sullen and sulky. They hadn't left their poverty-stricken villages to clean rifles. They wanted to make their fortunes. They wanted action.

They were about to get it.

The attack came suddenly, without warning and at the worst possible moment. The government troops must have been watching, waiting for the perfect time to strike.

Fergus heard the helicopter gunships first. The deep, throaty growl of the engines, immediately followed by the ominous chop of the rotor blades. The tree canopy swayed and shifted and rainwater came cascading down.

'Shit,' murmured Fergus, as he looked up and saw the first helicopter overhead. 'Stand to! Stand to!'

The guerrillas ignored the command. Most of them simply panicked and started to run towards the boats, unaware that a gunner was already lining them up through the sights of the heavy machine gun mounted in the doorway of the gunship.