The ban on legal highs of any kind shows the Tory government are "miserable sods" who want to stop people having fun, the former chief advisor on drugs has said.
Professor David Nutt, who was sacked by then-home secretary Alan Johnson after protesting the reclassification of cannabis, told NME that nitrous oxide – a primary target of the psychoactive substances bill - had been used mostly without incident for 200 years.
"Some of the greatest minds in the history of Britain, the people that made British science, used nitrous oxide," he said.
"Wordsworth and the Romantic poets used nitrous oxide. The guy who popularised the use of nitrous oxide, Humphry Davy, was friends with Wordsworth and Coleridge.
"Nitrous oxide has been around as a medicine and a way of people understanding a different way of feeling for 200 years. Banning it now is pathetic."
He added: "They'll be putting yellow stars on drug takers' foreheads soon. It is a peculiar attack on being anything other than a member of the Bullingdon Club - but they did drugs, didn't they? I think this is just about young people enjoying themselves, and they hate that because they're miserable sods."
Nutt, who is a global expert on drug harms, said legal highs were hardly responsible for any deaths at all.
"They've concocted and continue to perpetuate this lie," he said.
"In fact, my view is that there are almost no deaths from legal highs at all... Head shops don't sell illegal drugs. They're the good guys. They're selling drugs which are known to be relatively safe."
Nitrous oxide, otherwise known as laughing gas, is the second most used recreational drug in the UK after cannabis, with Home Office figures suggesting it was taken by 470,000 people in 2013/14 – up by about 100,000 on the previous year.
It is particularly popular among young people, with 7.6% of 16-24-year-olds having tried it in the last year, compared to 4.2% for cocaine, 3.9% for ecstasy and 1.8% for ketamine.
The drug is usually taken by filing a balloon using a gas canister and inhaling and exhaling it until its effects take hold.
These include giddiness, mild euphoria and laughter and usually last for about a minute.
"If you take one of the canisters that they use for treating women in childbirth for four or five days then you will certainly end up damaging the vitamin B in your blood, but two balloons every hour for a couple of hours aren't going to affect anyone," Nutt said.
Nitrous oxide is used in whipped cream, so prosecutors will have to prove suppliers sold it "recklessly" if they are to secure convictions under the bill.