Gonorrhea could be untreatable by 2015 because it is becoming harder to find antibiotics that treat it, the BBC has reported.

This follows news that there has been a sharp increase in the number of cases of the sexually transmitted infection gonorrhoea - up 25% in 2011.

The BBC quoted Professor Cathy Ison, head of the National Reference Laboratory for Gonorrhoea which is part of Public Health England, as saying: "Hopefully by raising awareness we can at least buy some time and look at new ways in which we can prevent it from becoming untreatable."

"But there is a possibility that if we don't do something then it could become untreatable by 2015."