The number of gonorrhoea cases diagnosed in England has reached its highest level in more than 40 years, official figures show.
A total of 56,259 cases were reported in 2018, up by more than a quarter (26%) from the previous year.
This is the largest number since 1978 and an increase of 249% in the last decade, according to Public Health England (PHE).
The rise of gonorrhoea, which is largely due to increases among gay, bisexual and other men who have sex with men, is of particular concern due to the emergence of extensively drug-resistant gonorrhoea, health officials said.
Three cases of this strain were reported in England in 2018.
Overall, cases of sexually transmitted infections (STIs) in England also rose last year.
A total of 447,694 diagnoses were reported, up by 5% from 424,724 in 2017, the data shows.
Cases of syphilis increased by 5% to 7,541, and have more than doubled from 2,847 diagnoses 10 years ago.
Dr Gwenda Hughes, head of STI surveillance at PHE, said: “The rise in sexually transmitted infections is concerning. STIs can pose serious consequences to health – both your own and that of current and future sexual partners.
“No matter what age you are, or what type of relationship you are in, it’s important to look after your sexual health.
“If you have sex with a new or casual partner, make sure you use condoms and get regularly tested.”
Chlamydia remained the most commonly diagnosed STI, accounting for 218,095 – or almost half – of new diagnoses in 2018.
However, the number of chlamydia tests taken by young people dropped by 1% compared with 2017.
A total of 1,304,113 people aged 15 to 24 were checked for the infection, a drop of 22% since 2014.
Debbie Laycock, head of policy and public affairs at Terrence Higgins Trust, said the figures show the need for “urgent action to improve the state of the nation’s sexual health”.
“We are yet again seeing soaring rates of syphilis and gonorrhoea, and increases in the number of people attending sexual health services, which is happening against a backdrop of central government stripping £700 million from public health budgets in the last five years,” she said.
“The Government cannot bury its head any longer, the consequences of under-investment and services struggling to meet demand is plain to see with these STI numbers.
“Progress has sharply halted in tackling rates of chlamydia, with rates up 6% last year, while there continues to be a decline in the number of chlamydia tests being carried out. This is clear evidence that removing access to testing is having a direct impact on the rates of chlamydia with cases now rising.”