“May you of a better future, love without a care,” wrote the artist and film-maker Derek Jarman in his final year. It’s a line that returned to me last month as I rode the Eurostar back to London with my colleagues, Marc and Phil. After meetings with sexual health activists from across Belgium, Marc took out the pill-holder he keeps in his pocket when he travels, and swallowed the medication he takes every day. Doing so reminded Phil and I that we should do the same, each of us gulping down a generic formulation of a tablet called Truvada. This, as Jarman would say, is our better future.

The pill regime is called PrEP (pre-exposure prophylaxis). Marc, who was diagnosed with HIV more than 30 years ago, towards the end of his teens, takes the pills to keep him healthy and well. Taking the pills also means he can’t pass on HIV to any sexual partners. Phil and I, who don’t have HIV, take the pills to prevent us getting it should we be exposed.

It is this combination of prevention methods – the testing and treatment of someone with HIV, and the availability of PrEP to those most likely to be exposed to it – that led to a 71% fall in incidences of HIV among gay and bisexual men between 2014 and 2018, one of the most dramatic decreases ever registered. The drop was most profound in London, where PrEP is available on the Impact trial coordinated by Public Health England (PHE). Cities providing PrEP, such as San Francisco, New York and Paris, experience the sharpest falls in HIV.

For those of us who work in sexual health, these falls are unprecedented. After two decades of ongoing increases in HIV, data like this is welcome news, especially given recent stalling in the development of an HIV vaccine. PrEP, when used as prescribed, is almost 100% effective. It has few side-effects, can be taken by everyone (despite popular myth, it’s not just for gay men), and could save health services millions of pounds in HIV treatment.

And yet PrEP is still not available through NHS England. After a court case brought by the National Aids Trust in 2016, NHS England implemented the Impact trial, making PrEP available to a limited number of people through sexual health clinics. With 20,000 people now on the trial, along with an estimated 10,000 people buying their PrEP online, there is a clear demand for the drug. Yet the trial will cease recruitment this summer, and is scheduled to close in October. Though it’s likely that PrEP will be available as a fully commissioned service later in the year, we still don’t know for certain if, and when, this will take place.

Scotland is leaps ahead, having made PrEP available through the NHS several years ago. That’s another crucial lesson that we’ve learned from the earlier implementation of PrEP in Scotland: offering the drug brings people into sexual health services who otherwise wouldn’t be using them. PrEP in Scotland has become a wonder intervention that also draws people towards HPV vaccination, hepatitis testing and treatment, and psychosexual services.

Recent data, including PHE’s report, shows that access to PrEP reflects existing HIV and health inequalities. As a researcher who has explored PrEP acceptability and access, it comes as no surprise to me that access to and use of the drug is highest among gay, cisgender white men who live in London. People who know how to navigate health services, are able to get to the front of a queue for a rationed service (such as the Impact trial), or who have peers who tell them about PrEP, are the ones who benefit most from prevention technology.

But it’s not just social advantages that influence PrEP take-up. Public Health England data shows that falls in HIV were greatest among white gay men, with smaller drops in black and Asian men. Experience of homophobia and racism in health services, stigma surrounding HIV, and a lack of awareness about available services may make it harder for these groups to access PrEP. Gender plays a role too: women who could benefit from PrEP are less likely to know about it than men, and less likely to access it. We hear stories of women who could benefit from PrEP leaving sexual health clinic appointments without it being discussed, no wiser of its benefits to them.

Making PrEP fully available in England will help resolve some of these inequities. If, as is widely expected, PrEP becomes part of routine sexual health commissioning at the end of the Impact trial, then further investment will be required to ensure that everyone who needs PrEP can access it, including communities that don’t currently benefit from the drug.

None of this will happen unless local authorities (which foot the bill for PrEP sexual health visits through their public health budgets) are properly funded. At a time when local authorities have had their budgets stripped and endured successive cuts, it’s ludicrous to expect councils to cover these costs. If Matt Hancock, the health secretary, is serious about tackling HIV, the government needs to make a commitment to properly funding local authorities to deliver the drug. In this new HIV prevention era, in this better future, PrEP can’t remain a niche option reserved for people like me.

• Dr Will Nutland is the co-founder of advocacy group PrEPster.info

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