Sexually transmitted diseases among young people are soaring, with record numbers of new infections diagnosed last year.
A government report says the increase in cases of HIV, chlamydia and syphilis is driven by increases in risky behaviour and a perception that the diseases are "trivial". But infected patients face serious difficulties in getting treatment; in some areas, fewer than 30 per cent are being seen within the government target of 48 hours.
The annual report by the Health Protection Agency (HPA), Mapping the Issues, says no part of the country is unaffected. Almost 700,000 new diagnoses of sexual diseases were made last year, a 62 per cent increase on a decade ago. The most common infection is chlamydia, which exceeded 100,000 cases for the first time in 2004, up 9 per cent on the previous year and more than three times higher than in 1994-95.
But the true figure could be up to six times greater because screening in some areas showed infection rates of 12 per cent in the 16-25 age group, compared with less than 2 per cent of confirmed diagnoses in the same age group for the general population.
Chlamydia is hidden, because it shows no symptoms in most people, who discover they are infected only when tested for other reasons. But if the bacterial infection rises up the genital tract it can cause serious problems including miscarriage, pelvic inflammatory disease and infertility. A national screening programme is being phased in which could account for some of last year's rise, specialists said.
There were 7,275 new diagnoses of HIV in 2004, bringing the total living with the condition to 58,300 - 5,000 more than in 2003.
The total includes those who have been diagnosed and an estimated 20,000 unaware of their infection, based on anonymous testing of blood given for other purposes, who could spread the disease unwittingly.
Most HIV infections were acquired in Africa, either by immigrants from the continent or people who visited it. The main route of infection in the UK is through sex between men, which accounted for 2,185 cases in 2004, the highest since 1990. Heterosexual HIV infections acquired in the UK have more than doubled from 227 in 2000 to 498 in 2004. The steepest rise in sexual infections was in syphilis, up 37 per cent last year to 2,234 cases. Most victims are gay men.
Professor Peter Borriello, director of the Centre for Infections at the HPA, said: "There is a more relaxed attitude to casual sex. People don't take that seriously so neither do they take protecting themselves seriously. There is a perception that these infections are trivial, treated with antibiotics. But HIV is serious: it is less of a fatal disease because of improvements in therapy but resistant strains are emerging."
He said surveys showed an increase in unsafe behaviour among gay men. There had been an outbreak of an infection, Lymphogranuloma venereum (LGV), not seen before in Britain, affecting 215 gay men mainly in London and Brighton. LGV is a type of chlamydia normally found in tropical countries. "We are seeing a trend of transmission of HIV that is resistant," Professor Borriello added. "So it is obvious that the transmitter knew they were infected and was taking anti-retroviral drugs at the time."
Caroline Flint, the Public Health minister, said: "The rise in sexually transmitted infections, including HIV, is a serious problem and tackling this has to be a priority. That is why we have committed £315m to modernise sexual health services, including a £50m advertising campaign to warn people of the dangers of irresponsible sexual behaviour and the top five infections including HIV."