An outbreak of highly drug-resistant "super-gonorrhoea" is sweeping across Britain and could become untreatable, medics fear.

A national alert was triggered by Public Health England last September after the rare strain of the sexually transmitted superbug was detected in 15 people.

The number of confirmed cases has now risen to 34 and, according to reports, there is "huge concern" among doctors that it is spreading across the UK. And experts said it is at risk of becoming untreatable if the only fully effective antibiotic remaining fails.

There have been efforts to track down the sexual partners of those infected with the disease, which can cause infertility.