The biggest sexual health campaign for 20 years was announced by the Government yesterday as figures showed HIV infections and other sexually transmitted diseases soared to record levels last year.

The biggest sexual health campaign for 20 years was announced by the Government yesterday as figures showed HIV infections and other sexually transmitted diseases soared to record levels last year.

John Reid, the Secretary of State for Health, pledged to make sexual health a priority with a £300m clinic modernisation programme after the Health Protection Agency (HPA) reported an estimated 53,000 people living with HIV in the UK. The latest figure is up from 49,500 last year, a quarter of whom are unaware they are infected. The total is estimated from anonymous blood testing.

The HPA said there were 6,606 new HIV infections diagnosed in the UK during 2003, but this figure was expected to rise to 7,000 after all data is collected. Most were among migrants, especially from Africa. Professor Pat Troop, the chief executive of the HPA said: "Each HIV infection prevented can save between £500,000 and £1m in treatment and lost productivity, meaning the UK faces rising costs as well as lost productivity."

Since 1995, all sexually transmitted infections have soared, with a three-fold rise in chlamydia to 89,818 cases in 2003, a doubling of gonorrhoea to 24,309 cases and an 11-fold increase in syphilis to 1,575 cases. The rise is continuing with cases of chlamydia, the commonest infection, up 9 per cent last year and syphilis up 28 per cent.

Professor Troop said the rise in cases was being driven by gay men and young heterosexuals engaging in risky behaviour. Sexual health services were under increasing pressure from the growing demand and fewer than a third of patients are seen within 48 hours. "If prevention efforts are to be scaled up to tackle these epidemics then sustained funding is required," she added.

The £300m programme announced by Mr Reid yesterday will run over three years and includes a £50m advertising campaign. There will be £80m for a national chlamydia-screening programme by March 2007 and £40m for contraceptive services. He said the campaign would focus on telling young people about the danger of irresponsible sexual behaviour. "Prevention messages are not getting through. We need to act now on sexual health and make it a priority."

Those at greatest risk from sexually transmitted infections are people aged between 16 and 24. Almost three quarters of all chlamydia cases in women and half of all those in men are in that age group, which is just 17 per cent of the population. The same age group accounts for 68 per cent of gonorrhoea cases in women and 40 per cent in men.

Sexually transmitted infections fell in the late 1980s and early 1990s in the wake of warnings about the threat from HIV. But as the HIV threat to heterosexuals in the UK was shown to be lower than had been feared, and the arrival of new antiretroviral drugs fostered the myth that HIV was "curable", complacency set in.

Professor Peter Boriello, head of public health at the HPA, said that studies showed young people had more sexual partners but were inconsistent in their use of condoms. "With increasing freedom there comes increased responsibility but we are expecting it of an age group that does not take responsibility. We need behavioural studies to understand what the barriers are to prevent people using condoms."

On HIV, the report, Focus on Prevention, shows that most case were from abroad, mainly Africa. There were 1,735 new diagnoses in gay and bisexual men in 2003 of which 1,400 (80 per cent) were acquired in the UK. Among heterosexuals there were 3,801 new diagnoses last year of which 341 (9 per cent) were acquired in the UK. About half of the 341 cases were among people born in the UK.

Ann Weyman, chief executive of the Family Planning Association, warned: "The single most important step to improving the nation's sexual health in the long term is the introduction of compulsory sex and relationships education in schools. At present, the minimum requirement is that the biological facts are taught. There needs to be a much broader programme across all schools which provides the skills and knowledge needed to negotiate relationships. Until this happens, the constant fire-fighting around sexual health will continue."

The Terrence Higgins Trust said the figures confirmed that the UK was "in the grip of a serious HIV epidemic". The chief executive, Nick Partridge, said: "We urge the Government to ensure that the campaign has high impact, is sustained and includes carefully targeted information for those most at risk from HIV and sexually transmitted infections."

'It never occurred to me that the test might be positive'

Joanne was infected with HIV by the first man she trusted enough to take to bed. She was 18 and aware of the risks of unprotected sex. During their two-month relationship she insisted he wear a condom but one time he removed it halfway through.

"So many of my friends had had more partners and were having unprotected sex and they got away with it. I went for the test only because my boyfriend had given me another sexually transmitted infection."

Joanne, now 22, is from north Wales and her partner was Ghanaian. She knows she was unlucky. But women are biologically twice as likely to contract the virus as men.

Her parents are separated and although her mother was supportive her father was shocked. "When I stayed with my dad and sister they'd scrub the bath with bleach after I'd used it. They'd hate me walking around without socks in case I cut my feet and bled on their things, and they bought baby-sterilising equipment and wanted me to have my own cutlery. It was humiliating.

"And now, if I meet somebody I like, I have to tell them about the HIV and there's never a right time to say it. It will always get in the way."