Former Deputy Prime Minister Nick Clegg has warned the government against enforcing a ban on poppers amid a review.

In January, Parliament voted to approve a blanket ‘legal highs’ ban that will prohibit the sale of drugs including alkyl nitrites (poppers), commonly used by gay men to help relax the anal sphincter muscles for anal sex.

Home Secretary Theresa May pushed through the legislation to make poppers illegal alongside substances such as nitrous oxide (laughing gas) – but conceded a review of the issue after expert recommendations and unrest among Tory MPs.

Conservative backbencher Crispin Blunt had outed himself as a user of poppers in a Parliamentary debate, while another, Michael Fabricant, also admitted to “trying” the drugs – though not for gay sex.

Former Lib Dem leader Nick Clegg waded into the row this week, as the law is now set to come into force on April 6, closing off the poppers trade.

If the government does decide to reverse its decision after review, poppers could be legalised again by the summer – but the Yorkshire-based companies who manufacture poppers warn they will be crippled or go bust before then.

Mr Clegg told the Guardian: “Poppers have been around for decades.

“The evidence shows they don’t pose any great risk to health, and that’s why they have never been banned before.”

“Frankly they could have been made exempt from the new act without the need for a review, but the government didn’t want to admit they had got it wrong.

“While there is a review ongoing, of course the legitimate businesses that produce poppers should be allowed to continue to operate.”

Rights charity Stonewall added: “It is clear to us that allowing a full ban to go ahead in April will cause confusion, and more importantly could put gay and bi men’s health at serious risk.

“People who use poppers will be forced to turn to illegal suppliers who could supply poppers containing unknown harmful substances or indeed more harmful illegal drugs.

“This is not acceptable and puts gay and bi men at risk.”