LONDON - One in five young Britons has sex with a new partner when travelling abroad, putting them at risk of contracting HIV and other diseases, researchers said on Thursday.

Most pick fellow Britons or Europeans, apparently believing this minimises the chances of HIV infection, but they are largely unaware of the dangers of other sexually transmitted infections.

With overseas travel soaring due to low-cost flights, holiday 'flings' represent a risky pattern of behaviour that should be better targeted by healthcare authorities, according to Dr Catherine Mercer of University College London.

Twenty three percent of men and 17 percent of women aged 16-24 reported having new sexual partners while overseas in the past five years, Mercer and colleagues reported in the journal Sexually Transmitted Infections.

The research was based on interviews with a random sample of thousands of people taking part in a national survey of sexual attitudes and lifestyle.

Britain already has higher rates of sexually transmitted diseases than other European countries. Mercer said primary-care surgeries, travel and sexual health clinics should do more to promote a message of safe sex abroad.

Groups deemed to be particularly at risk include young people on package holidays, as well as those travelling overseas for longer periods, such as gap year students.