Alex James, bass player of Britpop band Blur, revealed in his autobiography that he'd spent "a million pounds on champagne and cocaine".
According to the Home Office there are 800,000 cocaine users in Britain.
Colombia supplies 80% of the world's cocaine and Colombian President Alvaro Uribe invited celebrities publicly linked to drug use to visit his country to see the damage the cocaine industry has done. At our suggestion Alex took up the challenge.
In Colombia, Alex met the Vice-President, Francisco Santos Calderon, who explained what he hoped the visit would achieve:
"[If a] person starts consuming coke, all that money comes here to finance landmines, destruction of the environment, terrorism, kidnapping, displacement.
"If I say it, they won't believe me. If you say it, because of what you saw, they'll believe you a lot more."
Can't survive without it
Alex, who no longer uses cocaine, visited an anti-narcotics base where the Colombian military were overseeing the chemical spraying of thousands of hectares of coca plantations.
Vice-President Santos has called this spraying ineffective and insists that the plants be dug up by hand.
This is highly dangerous work as they are often shot at and the coca fields can be land mined. Of the unit Alex spoke to, 32 were killed last year - that's 10% of the workforce.
Alex flew to El Charco, Colombia's biggest coca producing region. In makeshift labs, farmers turn the coca leaves into base cocaine, known as pasta basica. They then sell it on to be turned into cocaine.
Alex spoke to farmer Sotero Micolta, who started growing coca plants six years ago. Prior to that he earned $132 per month, as a coca farmer he can earn $550.
Coca can be harvested four to six times a year
He explained how he had no choice but to grow coca:
"Without it we can't survive. If the government gave us an alternative and money to set up a business then nobody would grow coca around here."
Back in Bogota, Alex meets a dealer, who explains how the drugs get into Europe through Spain, and how Spanish mafias distribute it to the rest of Europe.
The dealer told Alex about the European market for the drug:
"I think most Europeans see it as a requisite for a party or a gig. If I don't want a drink, I don't have one.
"If I don't want a line I don't have one. It's a personal choice."
Another link in the supply chain is the contract killer, a hit man who works for some of those who run the trade.
Alex discovered that in Colombia, cocaine and violence are inextricable.
When Alex met him, the hit man was disguised as a taxi driver, but with a gun hidden under his leg.
"It's a long way from a cheeky line at a dinner party in Notting Hill. It's terrifying." said Alex.
The hit man tells Alex business is good, and mostly drug-related:
"In recent years everything that goes down here in Colombia is related to the drug trade.
"This is a cancer that is affecting this country, but it's a cancer that makes money all over the place."
Shortly after the film was completed word came that he himself had been murdered.