Using a condom should be as natural as using a mobile phone or putting on a seat belt, says Health minister

The Government yesterday used provocative pictures of youngsters in their underwear to launch a safe sex campaign targeting 18- to 24-year-olds "on the pull".

The £4m campaign, launched yesterday, will be shown on national TV, online, and in print and radio advertisements. It aims to combat the rising number of sexually transmitted infections (STIs) among young people. One in fiveunder-24s say they do not take condoms with them on a night out.

The campaign features teenagers wearing underwear with the slogans: "I've got gonorrhoea" and "I'll give you one". The TV ad, which will appear from 20 November, shows couples with the name of an STI displayed on clothes or jewellery. It aims to show that in real life such infections are not so easy to spot.

Health groups have backed the drive, but also claim that a further £46m was pledged by the Government. Rates of STIs have risen since the 1990s; one in nine sexually active young people has chlamydia. According to the Health Protection Agency, diagnoses of sexual infections rose by 3 per cent last year, to 790,000. The biggest rise was seen in syphilis, which rocketed by more than 20 per cent, but increases were also seen in genital warts and herpes.

Caroline Flint, the Public Health minister, said: "It is vital that we deliver strong messages to prevent STIs. The aim of this campaign is to make carrying and using a condom among this age group as familiar as carrying a phone, lipstick or putting on a seat belt."