A Home Office minister has explained that poppers can have “beneficial” effects for men having anal sex – hinting at a U-turn ahead of a vote to ban them.

Parliament will vote today on a blanket ‘legal highs’ ban that will prohibit drugs including alkyl nitrites, commonly used by gay men.

Home Secretary Theresa May will today push ahead with legislation to tackle legal highs by implementing a blanket ban on the sale of “psychoactive substances” – with those found guilty of selling them facing up to seven years in jail.

Under the legislation, the drugs commonly known as poppers would be made illegal alongside substances such as nitrous oxide (laughing gas).

The Advisory Council on the Misuse of Drugs (ACMD) and the Commons Home Affairs Select Committee both recommended that poppers – commonly used among men engaging in anal sex – should be exempt from the ban, but the government has declined to add an exemption in time for today’s vote.

However, a letter to the Select Committee from Home Office minister Mike Penning reveals the government is considering backing down on the issue, after “careful consideration” – recognising their “beneficial” effects.

He wrote: “The Government recognises that representations have been made to the effect that ‘poppers’ have a beneficial health and relationship effect in enabling anal sex for some men who have sex with men, amid concern about the impact of the ban on these men.

“In consultation with the Department of Health and the Medicines and Healthcare products Regulatory Agency (MHRA), the Home Office will now consider whether there is evidence to support these claims and, if so, whether it is sufficient to justify exempting the alkyl nitrites group.”

He added that the drugs could be exempted at a later date even if the bill passes, adding: “The Bill enables the Home Secretary (after statutory consultation with the Advisory Council on the Misuse of Drugs)… to add to the list of exempted substances to the Bill.

“The Government intends to complete such consideration in time to enable any such draft regulations to be laid before both Houses and approved before the summer recess should the Government conclude that a case had been made to include alkyl nitrites in the list of exempted substances.”

Tory MP Mike Freer, who had previously warned about the proposed ban’s impact, welcomed the climbdown.

He said: “In response to this announcement Mr Freer said: “I welcome this approach and that the Government has responded positively to representations made by myself, Prowler, National Aids Trust and others.

“I am also pleased the Government will move swiftly to conduct an immediate independent review into the medical evidence related to the recreational use of poppers.

“Although we would have preferred to not have been in this situation to start with, the fact is there remain concerns about the potential harms from using poppers. But through an independent review of the evidence, the issue should be resolved by July 2016.”