Nick Clegg has attacked the Conservative Party for refusing to consider a reform of the drug laws.
The Deputy Prime Minister called for a new approach and an end to the world's "blinkered view" on the problem, saying: "The status quo is failing".
The Deputy Prime Minster spoke out after a visit to Columbia, where he witnessed first-hand the devastation caused by the drugs trade.
He met former paramilitaries, guerrillas and the country's president, The Observer reported.
Writing in the paper on Sunday morning, Clegg said: "Many people in Britain and the rest of Europe will still be unaware of the impact drug use in western nations has on countries on the frontline of the drugs trade. It is only right, then, that we play a part in helping to find a solution.
"It is why I am a firm believer in the need for a royal commission in Britain and why I am so disappointed at my coalition partner's refusal to engage in a proper discussion about the drugs problem."
If Britain was fighting a war that killed 2,000 people a year, there would be an "outcry", Clegg said.
His comments are similar to those made by David Cameron, before he became Conservative Party leader.
Cameron once called for "alternative ways" to tackle drugs, and criticised politicians for "posturing with tough policies".
But his stance has since hardened, leading campaigners to accuse him of "chickening out".