Ministers have ordered a new £45m campaign to shock teenagers into using condoms, as Britain's worsening sexual disease epidemic is revealed in new figures this week.

Ministers have ordered a new £45m campaign to shock teenagers into using condoms, as Britain's worsening sexual disease epidemic is revealed in new figures this week.

The number of sexually transmitted infections will be shown to be heading for one million a year in an official report released on Thursday.

Ministers - disturbed by evidence that up to one-fifth of young men now have chlamydia - believe "shock tactics", last used to raise awareness of HIV in the 1980s, are needed. If undetected, chlamydia can cause pelvic inflammation, infertility and, in women, greater risk of ectopic pregnancy.

John Reid, the Secretary of State for Health, has been told that the Government must shatter complacency among the young about the risks of unprotected sex, with the biggest safe-sex campaign and education drive for 17 years.

Mr Reid is to unveil a three-year awareness-raising campaign on Thursday together with extra cash for screening and treatment centres. Walk-in screening centres in shopping centres, sports halls and even schools will also seek to reverse infection rates.

The advertising blitz, scheduled for next year, is intended to be a modern version of the controversial "tombstone" campaign ordered by the Thatcher government in 1987.

The announcementhas been timed to coincide with the latest figures on sexually transmitted infections (STIs) from the Health Protection Agency. They are expected to show rising rates of HIV/Aids, syphilis and genital warts, with the number of new STIs now heading towards one million a year.

It is the dramatically increasing rate of chlamydia, particularly among the young and those from ethnic minority communities, that is causing most concern. Pilot walk-in screening centres confirmed fears of a growing "reservoir" of infection among young people.

The first annual report of the National Chlamydia Screening Programme found that one in eight teenage girls assessed were carrying the disease. The rate was even higher, almost one in five, among men aged between 20 and 24.

The Government's White Paper on public health announced a major expansion of the screening programme, as well as a target to provide an appointment in a treatment clinic within 48 hours of referral.

Ministers are under growing pressure to do more to help curb the spread of sexual diseases. Dr William Ford-Young, spokesman for the Royal College of General Practitioners, said: "The Government has known about this problem for a long timenow but has been dragging its heels when it comes to funding. More needs to be done and quickly. If we don't deal with this problem we face the prospect of more women becoming infertile in later life," he told a recent conference.

A senior civil servant at the Department of Health admitted that previous campaigns had failed to have much effect in changing behaviour.

"It's a long time since the 'Don't Die of Ignorance' HIV awareness campaigns and nothing like that has been tried since," the civil servant said.

"There is an acceptance that we need to get back to that sort of stark warning if we are going to get the message through."

Stephen Coate, director of the Gay Business Association and chairman of London Pride, said: "In the gay community, this kind of thing has already been widely campaigned for. The biggest hindrance has been a lack of consistent and wide-ranging sexual health education for children."

Internal estimates of the scale of the new campaign suggest it will run for three years at a cost of £15m a year.

Sir Norman Fowler, the then Health Secretary, was criticised for scare-mongering when he ordered a £20m-a-year education and advertising drive in 1987.

However, the campaign, which included leafleting every home in Britain, is regarded with hindsight as a qualified success.

'Nobody bothers with condoms any more'

Ria Moody, 17, is studying for A-levels at Bishop Luffa comprehensive school in Chichester, West Sussex. She has been in a relationship for four years.

"Loads of people are on the Pill now, so nobody bothers with condoms any more. Among people my age, pregnancy is a much bigger issue than sexually transmitted diseases.

"A lot of my friends, if they have unprotected sex, would get the morning-after pill, but wouldn't get themselves checked for STDs.

"This kind of campaign sounds like a good idea. Most people I know are aware of Aids, but not so much about other sexually transmitted diseases, especially those that don't have obvious symptoms. A lot of people also still associate Aids and HIV with homosexuality. If they're in a mixed-sex couple they don't think it's an issue."

'We need to be scared'

Nell Chislett, 29, works in publishing and lives in Islington, north London. She has been single for 18 months.

"Too many people feel that, apart from HIV, everything else can be cured and it doesn't really matter.

"We need to be scared to a certain extent. Most people my age are pretty blasé about safe sex."

'People are more worried'

Isobel Mackintosh, 21, is studying for a BA in modern history at Durham University. She has been in a relationship for six months.

"I guess over the past couple of years people have become more worried about STDs, particularly chlamydia and the affect it can have on fertility. But there are still too many who only have a rough idea of the dangers involved - and too many who have the 'it won't happen to me' attitude. A lot of people only think about the immediate, but they often don't consider who that person has slept with before, and who they have slept with. People don't realise just how contagious these things are."