One British researcher said yesterday that the return of the bathhouse culture among gay and bisexual men, involving sex with multiple partners, could provide the scenario in which a preventive pill might be taken.

Sheena McCormack, a specialist in HIV prevention and reader in clinical epidemiology at Imperial College London, said: “The party scene involving multiple sexual partners is definitely back in London and probably in most European cities. There is metrosexual mixing involving gay, bisexual and some heterosexual cases. We estimate new HIV infections in gay men in London are running at 3 per cent a year”.

Her clinic already offers “post-exposure prophylaxis” to people who have had unprotected sex with someone in a high-risk group, involving a month-long course of treatment with three drugs. But a preventive drug would provide an extra option. “People could pop a pill on a Friday night and be covered for the whole weekend,” she said.