Dozens of protesters have inhaled laughing gas outside Parliament today to show their opposition to a new Psychoactive Substances Bill.
The government wants to pass new laws making it illegal to sell any "psychoactive substances", other than alcohol, caffeine and nicotine.
The Psychedelic Society today organised the mass inhalation using the hashtag #mymindmychoice from 3pm.
In a blog post published on the Huffington Post director of The Psychedelic Society, Stephen Reid, said that it should be up to the consumer if they want to take the risk and use the drug dubbed 'hippy crack'.
He said: "The Psychedelic Society believes prohibition is an affront to the basic right of bodily autonomy: the right to do whatever we want with our own bodies. Yes, the use of psychoactive substances can be risky, but it should be for individuals to decide whether or not to take the risk.
"People should be able to buy, sell and use whatever substances they want, so long as there's no harm to others."
The Psychoactive Substances Bill had its third reading on Monday 20 July and includes plans to crack down on legal highs.
Under the bill, possession of nitrous oxide will remain legal, as long as there is no intent to supply but the bill could mean up to seven years in prison for people who provide drugs to others, according to Sky News.
There have, however, been 17 fatalities related to the use of laughing gas in the UK between 2006 and 2012, according to the BBC.
New figures suggest that it is the fourth most used drug in the UK and that 400,000 used it in 2013-14.
Laughing gas is conventionally used as an anaesthetic during dentistry and child birth and in the manufacture of whipped cream, a number of Premiership footballers have been caught using the substance in the past year.
On their Facebook page, The Psychedelic Society, said: "Today's the day! We've already been kicking prohibition's ass on Sky News, BBC Radio 5 Live and BBC Bristol.
"All we need now is you to join us. If you support the legal regulation of drugs as a fairer and safer solution, come down to Parliament Square today."
A number of deaths have been linked to so-called 'legal highs' -- drugs that produce a psychoactive response but are not currently classified under the UK's drug rating system.
Professor David Nutt, a psychiatrist and neuropsychopharmacologist based at Imperial College London, says that although there is a risk.
"Laughing gas is an unusual anaesthetic and pain reliever and when given in hospital it is mixed with the oxygen which our bodies need," he told the Ham&High.
"I want to emphasise that the risks of nitrous oxide, while they exist, are lower than those of alcohol and most other drugs. Problems occur when people take it recreationally without getting oxygen.
"In hospitals, the gas in the tank is already mixed with oxygen whereas in recreational use it is usually pure, so users must be responsible for their oxygen."