Uruguay has become the first country to legalise the growing, sale and smoking of marijuana.
A government-sponsored bill approved by 16-13 votes in the Senate provides for regulation of the cultivation, distribution and consumption of marijuana and is aimed at wresting the business from criminals in the small South American nation.
Cannabis consumers will be able to buy a maximum of 40 grams (1.4 ounces) each month from licensed pharmacies, as long as they are Uruguayan residents over the age of 18 and registered on a government database that will monitor their purchases.
When the law is implemented in 120 days, Uruguayans will be able to grow six marijuana plants in their homes a year, or as much as 480 grams (about 17 ounces), and form smoking clubs of 15 to 45 members that can grow up to 99 plants per year.
Registered drug users should be able to start buying marijuana over the counter from licensed pharmacies in April.
Previously the use of marijuana was legal in Uruguay but the cultivation and selling the drug was not.
Vicky Pryce, who was jailed for swapping speeding points with ex-husband Chris Huhne, has called for a "different approach" to tackle drug-related crime - although she fell short of calling for decriminalisation.
Ms Pryce, who was speaking at an event at the Cheltenham Literature Festival to promote her new book Prisonomics, said that helping addicts stay off drugs was better than imprisonment.
She told the audience: "On the decriminalisation of drugs ... evidence-based policy, absolutely. Obviously the decriminalisation of some types of drugs would help.
"Prison has given them nothing at all to help them - quite the opposite. So a different type of approach to people taking drugs is the thing that we absolutely need."
The recommendations are expected to set off a bitter coalition row, with Home Secretary Theresa May resisting any significant changes.
A review ordered by Nick Clegg, the deputy prime minister, and due to be published before Christmas, is expected to suggest Britain could benefit from emulating two American states where the use of recreational cannabis is legal.
Cannabis worth £3.5m was seized by 130 police officers in early morning raids across south Wales and the west of England today.
Eight arrests were made by police and £400,000 in cash was discovered in the crackdown operation.
A large cannabis factory was later found and destroyed by authorities in Cardiff, and further raids were made in Newport, Bath and Bristol.
Detective Inspector Paul Latham, who led the operation, said: "Operation Pristina was put in place to target individuals believed to be involved in the cultivation and supply of cannabis across South Wales and the west of England.
"During the course of this operation we have successfully disrupted many of those who have been suspected of dealing in drugs."