HOWZAT

But many middle-class Britons, who might consider themselves eco-friendly, appear to believe that their cocaine use is a “victimless crime” and are unaware of its impact on the environment.

“Obviously, for a hard-core drug addict this makes no sense,” said Mr Calderon.

“But for somebody who drives a hybrid, who recycles, who is worried about global warming - to tell him that that night of partying will destroy four square metres of rainforest and damage even more the environment makes sense and might lead him to make another decision.”

Europe is going through a boom in cocaine use among the wealthier sectors of society comparable to that seen in the USA 25 years ago.

Mr Calderon said law enforcement authorities in the UK were tough on drug trafficking, but said Britain should perhaps introduce US-style drug testing in schools and the workplace to drive down demand.

His comments may anger critics who say British users cannot be held responsible for the failures of the Colombian government in its ongoing battle with drug barons. Colombia's coca crop increased by 27 per cent last year, despite its US-backed crackdown, according to a UN report released in June.

But Mr Calderon claimed that his government’s war on drugs was succeeding, saying that FARC suppliers had been left short of cash to pay producers and forced deeper into the jungle - which he acknowledged created a new set of environmental problems. Bogota claims that though cultivation may have increased production has not because authorities have interrupted the growing cycle.

“We call it shared responsibility,” he said. “We can’t do it on our own. We need everybody’s action - the police here, the police in Colombia, the authorities in both countries and the consumers too. If there is no consumption, there will be no production.”

If EU demand continued rising and improvements in Colombian security limited supply, growers and traffickers would increasingly turn to equatorial Africa with the risk of armed conflict on Europe’s doorstep, he warned.

“We should learn from experience, Colombia was not a producing nation in the late 1980s and early 1990s,” he said.

“This is happening from Sierra Leone to Senegal - you are seeing the impact it is already having, so it is just a matter of time when they will start growing coca in equatorial Africa.”

The continent’s resource wars over diamonds could pale by comparison, Mr Calderon said.

“It is a nightmare that we are hoping to stop from becoming a reality but I would not bet on that, I would bet it is something which is going to happen in the next five years,” he said.

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• 'Was it real?' The US bailout nightmare
• Iranian opposition plays the long game