Along with hundreds of others, I'll be inhaling laughing gas outside Parliament to protest the Tories' legal high bill

I lower the balloon from my lips and close my eyes. Sounds begin to slow down and seem further away. I feel like I'm moving at high speed, but through what, I'm not sure. My sense of time begins to slip away. I reach the deepest point of my journey. As quickly as I arrived, I return, blinking in the sunlight.

The whole experience has lasted less than a minute, and I'm left feeling energised and slightly disorientated. Within another few minutes, I feel totally back to normal.

The nitrous oxide experience is one familiar to large and increasing numbers of people - some 470,000 people used the gas in 2013/14, up 100,000 from the previous year. According to the Global Drug Survey, it's the second most popular drug in the UK, after cannabis. Typically, it's administered by releasing the gas from a cream charger into a whipped cream dispenser and decanting into a balloon.

The experience is quite unlike being drunk, and I have many friends that prefer it to alcohol. Yet under the proposed Psychoactive Substances Bill, the sale of nitrous oxide for recreational purposes would be banned, along with the trade in every “psychoactive substance” except for alcohol, caffeine and nicotine.

The prohibition of certain psychoactive substances is an affront to the basic right of bodily autonomy: the right to do whatever we want with our own bodies. In this sense, there are connections to movements for sexual and reproductive rights. As Ethan Nadelmann, Executive Director of the Drug Policy Alliance, puts it: “Nobody should be punished for what they put in their body, whether it's a cock or a joint”.

To make this point clear to the Government, hundreds of people will gather outside Parliament next month for a mass inhalation of nitrous oxide, organised by The Psychedelic Society. It will be a brief, tidy and symbolic action, intended to make a serious point about an outrageous infringement of personal liberty.

A vitally important question is at stake here: should you have the right to alter your own consciousness in whatever way you choose? The Government seems to think not, proposing that the only '"legitimate" altered states are those induced by the substances in beer, coffee and cigarettes.

The excuse often returned by government for restricting how we may alter our own minds is that it is protecting us from ourselves. Even if you accept this rather dodgy function of government, why allow alcohol (the cause of some 8,000 deaths each year) and smoking (the cause of around 100,000 deaths each year)? Or, for that matter, horseriding, skydiving and bungee jumping?

It's not as if the state is protecting us from a new and unknown threat. Nitrous oxide has been used recreationally since the 1700s, while naturally-occurring psychedelic substances like mescaline, psilocybin and DMT have been used by humans for tens of thousands of years.

As the independent, science-led drugs charity DrugScience says: “If the user of nitrous oxide is in good health, understands the risks, and avoids dangerous methods, nitrous oxide is one of the least risky drugs.” Any substance can be dangerous if used irresponsibly; the key to reducing harm is in education. Prohibition will do little to reduce prevalence, nothing to improve education, and is an disgusting affront to the liberty of the vast majority of people who use drugs responsibly.