Brooke Advisory Centres will be giving out advance supplies of emergency contraception to young people on a case by case basis.

It is worried that the long holiday over the Christmas and New Year period will see a huge rise in unwanted teen pregnancy if young people do not stock up on contraceptives in advance.

A spokeswoman said teen conceptions and abortion rates traditionally rose following the festive season.

The problem is compounded this year by the fact that there are only two working days in an 11-day period over the New Year.

This means teenagers will face more problems getting hold of contraceptives. The UK has the highest teen pregnancy rate in western Europe.

Surveys also show that up to 71% of young people are planning to celebrate the millennium with alcohol.

Research shows a strong link between alcohol and unprotected sex.

Alison Hadley, national policy officer for Brooke, said: "We are asking young people to think ahead about their contraceptive needs over the extended holiday and make sure they are well prepared to party safely and enter the new millennium without regrets."

Brooke's decision to provide advance supplies of the morning-after pill over the festive period comes after a similar initiative was launched by the British Pregnancy Advisory Service (BPAS) in the summer.

Unlike the BPAS scheme, which costs �10 a time, the Brooke scheme is free.

No lower age limit

Brooke says it has no lower age limit for providing the contraception. "It depends on the individual case," said a spokeswoman.

Young people can find out where to go for advice by ringing Brooke's helpline on 0800 0185023.

Usually the morning-after pill - which works up to 72 hours after sex - is only available on prescription.

But there have been calls for it to be made more easily available, particularly since World Health Organization research showed it was 50% more effective if taken within 12 hours of having unprotected sex.

It does, however, have side effects such as nausea and doctors advise it should not be used as a regular form of contraception.

The pill, which has a 75% success rate in preventing pregnancy, should also not be used by women with a history of blood clots or migraines that affect vision.

However, increased availability of morning-after pills has attracted criticism from anti-abortion groups.

The Society for the Protection of the Unborn Child, says it is abortion by the back door.

But Ann Furedi of BPAS said: "It makes sense for women to be prepared for the morning after. You don't wait until you have a headache to buy an aspirin - why should you wait until you've had sex to get emergency contraception?"