The ruling Labor Party argues that the switch, which will let most users off with a warning, will allow police to concentrate on battling harder drugs such as heroin and crack cocaine.

Home Office Minister Caroline Flint said the treatment of all drugs as equally harmful and dangerous "lacked credibility" with young people.

"This is not about legalization, it's about having to have a mature discussion about drugs, about the relative harms," she said during a debate in the House of Commons before the vote.

In Britain, possession of a Class B drug currently carries a maximum penalty of five years in jail.

Possession of a Class C drug carries a maximum sentence of two years, but the Home Office said that penalty is rarely invoked for first-time offenders, who normally receive only a ticket.

The government said that in most marijuana possession cases under the new rules, police would simply confiscate the drug and issue a warning to the offender.

But officers would also have the power to arrest those possessing small amounts of marijuana if public order were threatened or children put at risk.

Oliver Letwin, the Conservative home affairs spokesman, accused the government of seeking "spurious short term popularity" by introducing the legislation and said it would send the wrong message to impressionable teenagers.

"The tendency will be for more, rather than fewer, young people to be led into hard drugs," he said.

The reclassification was one of several recommendations from a House of Commons committee and an independent advisory group. Home Secretary David Blunkett rejected other recommendations that Ecstasy be downgraded from Class A to Class B and that "shooting galleries" be set up for addicts to use drugs in controlled conditions. –Sapa-AFP