At the root of the cocaine epidemic

The 300 arrancadores - literally, 'uprooters' - set off from the jungle camp before sunrise. Thirty or so Colombian soldiers, carrying sub-machine guns and grenades, cover their backs. The men have a long slog ahead of them through dense jungle.

We walk for nearly four hours - past deadly snakes and spiders, and destroyed guerilla encampments - before the men at the front of the column break into a clearing high in the Sierra de San Lucas and the cry goes up: 'La coca!' Now the back-breaking work must begin.

I watch as the men, working with spades, begin to strip the one hectare field of coca bushes. In this plantation alone there are thousands of the green bushes that have played a pivotal role in the country's bloody 40-year civil war.

The UN says Colombia supplies 60 per cent of the world's cocaine -

600 tonnes annually. The main players are the Revolutionary Armed Forces of Colombia, or Farc, the leftist peasant army which has attracted global attention for its high-profile kidnappings.

But the remnants of the far-right paramilitary groups formed to protect farmers from Farc land-grabs are also involved: these demobilised paras trade cocaine by the tonne.

Until recently, the government's favoured method of tackling the coca plantations - always found at high altitude and impossible to access by road - was aerial fumigation. But the tactic has proved controversial and at times ineffective. Pilots have to find the fields in vast expanses of jungle, and neighbouring countries complain when drifting clouds of herbicide damage legitimate crops. Last Monday in The Hague, Ecuador began a lawsuit against