The number of cases of both syphilis and gonorrhoea has risen, according to new figures from Public Health England (PHE).
Data shows that there were more than 7,000 cases of syphilis reported in 2017, a 20 per cent increase on the previous year and a level not seen in this country since 1949.
Meanwhile, gonorrhoea has gone up by 22 per cent to almost 46,000 cases, with experts warning that some strains are becoming increasingly resistant to the drugs being used to treat them.
Sexually transmitted infections (STIs) are at their highest levels among young people aged 15 to 24 years, while gay, bisexual and ethnic minority groups were found to be most at risk of catching one of the diseases.
Overall, the number of STIs has remained stable in England, with roughly the same number of cases being reported last year as in 2016.
However, testing for STIs in contraceptive clinics was found to have decreased significantly. Lobbying groups warned that this could be due in large part to cutbacks on NHS resources, but it was also suggested that better home testing kits might have been partly behind the decrease.
Last year, PHE launched a campaign aimed at raising awareness of the importance of safe sex, with particular focus on promoting condom use among young people.
Meanwhile, in March, the fist case of so-called super-gonorrhoea was detected in the UK in a man who had travelled to Asia and had sex there.
Concern is increasing that with cases of the STI on the up and antibiotics increasingly being used to treat it, resistance to the drugs will emerge and many could be ineffective should more incidences of super-gonorrhoea arise.
Both gonorrhoea and syphilis are typically treated with a course of antibiotics, but syphilis can be especially dangerous.
If the infection has been present for less than a year, a short course of penicillin may suffice, but any longer than this and more doses are likely to be necessary to clear the infection.
Should it go untreated, syphilis can damage the heart, blood vessels, brain and nervous system, causing blindness, paralysis and even death.
It may be that in the future, pharmaceutical companies are required to develop new drugs to treat increasingly antibiotic-resistant STIs.