special to the Chronicle by London-based Bernd Debusmann, Jr.
Under current law, it is illegal for British citizens to consume or possess cannabis.
Estimates vary on the financial impact of legalizing and taxing the drug, a longstanding proposal by reform advocates. A recent study by the Institute for Social and Economic Research found that the government would gain up to £1.25bn a year. A 2011 study by the Independent Drug Monitoring Unit found the amount could range from £3.4 billion to £9.5 billion per annum, with a best estimate of £6.7 billion per year based on current market prices.
Commenting on the protester's demands, Peter Reynolds of Clear UK, a Norwich-based organization which seeks to reform cannabis laws, said that both studies are likely underreporting the real potential value to the British government and taxpayer.
"All the estimates are based on self-reporting of cannabis use," he said, adding that people were reluctant to admit to what is a criminal activity under current law.
Reynolds added he believes that cannabis reform's potential economic benefits are currently outweighed by political considerations.
"Britain is obsessed with cannabis psychosis stories, so we cannot start talking about rational things like cost. There is not the same intelligent discussion going on as in the United States," he said.
This view was echoed by Rupert George, the head of communications for Release, an organization which lobbies for drug laws to be based on public health issues rather than criminal justice.
"There is far more entrenched 'reefer madness' than in the US, with the dominant issue being about psychosis," he said. "The idea of a regulated drug market for cannabis, or any other drug, is politically a long way away."
While the British government's official stance is that cannabis has no proven medicinal value, in March 2013 the government announced that Sativex -- a cannabis based mouth spray produced by GW Pharmaceuticals -- could be prescribed to multiple sclerosis patients.
Alan Pavia, a spokesman for NORML UK (a British affiliate of the US-based National Organization for the Reform of Marijuana Laws), which organized Wednesday's protest, said that the rescheduling of Sativex demonstrates the British government's double standards with regards to medical cannabis.
"Now GW Pharmaceuticals has a license to grow marijuana for Sativex. It would seem that Sativex is scheduled in a different manner to protect this company," he said.
Through a spokeswoman, Home Office Crime Prevention Secretary Norman Baker said simply that "the government has no plans to legalize cannabis."
Currently, ten EU countries and 20 American states allow for the medical use of marijuana. Some countries, such as the Netherlands, legally regulate the recreational use of the plant, while others, such as Portugal, have decriminalized possession. Two American states -- Colorado and Washington -- have legalized recreational use of marijuana.