The government's Health Protection Agency revealed yesterday that new diagnoses of sexually transmitted diseases in England, Wales and Northern Ireland rose by four per cent overall last year to more than 708,000.

It also found that long delays in treatment were exacerbating the problem.

The Family Planning Association's chief executive, Anne Weymann, said: "Treating sexually transmitted infections and their consequences costs the NHS an estimated £1 billion a year.

"Fast access to treatment is essential to prevent the spread of infection and makes economic sense, yet waiting times are as long as six weeks."