HIV transmissions between gay and bisexual men have fallen 73% since 2014, according to Public Health England figures.
The decrease has been attributed to the introduction of the pre-exposure prophylaxis pill (PrEP), which is freely available in Scotland and Wales for people at high risk of exposure to HIV.
There is less access to the pill in England, where people must enroll in a test that began in 2017.
It is known that at least 15 people contracted HIV while on the waiting list for PrEP.
Clinical trials have shown that PrEP is most effective when taken in two particular ways, one regularly every day, or in larger doses before and after having sex.
It is believed that both methods, when followed correctly, are almost 100% effective in preventing transmission.
The drug is primarily aimed at men who have unprotected sex with other men, as well as people whose partners have HIV.
It is not used by those who already have HIV, who receive different treatments.
The transmission of the virus has plummeted since 2014, when the new figures begin, and were reduced from 2,300 to only 800 in 2018.
According to Public Health England data, 93% of the estimated 103,800 people in the United Kingdom living with HIV have been diagnosed, and 97% of them are receiving treatment that suppresses the virus.
Health Secretary Matt Hancock said last year that he wanted the United Kingdom achieve a zero transmission rate by 2030.
Activists have asked that PrEP be more widely available.
Phil Samba, a PrEP user and member of the Prepster campaign group, said the figures show how effective PrEP was and rapid access to HIV testing and treatment.
Samba said the government should “control and finance a full PrEP service now.”