Research by the FPA - formerly the Family Planning Association - showed that 13-year-olds were ill-informed about abortion and wanted to know more about sex, pregnancy, contraception and abortion.

Of a focus group of 50, more than half knew very little about abortion and more than a third said they did not know where to go for advice about an unplanned pregnancy.

FPA policy officer Tanya Procter said: “Abortion is usually tackled through debate, often in religious education lessons. It is rarely covered in the context of sex and relationships.

“We are not saying that all young people who get pregnant should have abortions, but they should know about the choices that are available.”

Britain has the highest rate of teenage pregnancy and abortio in Europe.

Doctors have reported a rapid rise in sexually-transmitted diseases among teenage girls.

Abortion figures released this week show that while the total number of terminations in Britain has fallen by 2.3 per cent, the figure for under-16s showed the smallest decline.

In Britain, one in five pregnancies is terminated - around 175,000 a year. In 1999, 36,257 teenagers had abortions in England and Wales, including 3,578 under-16s - down from 3,759 in 1998.

The booklet, Abortion - just so you know, was shown to 800 teenagers in schools and youth clubs who liked its informal and colourful style, the FPA said.

Anne Weyman, FPA chief executive, said: “The anti-abortion lobby will no doubt criticise our booklet, but our research shows that young people are clearly telling us that they want and need more information on all aspects of sexual health.”

The FPA is a member of Voice for Choice, a campaign to make early abortion available to more women.

“Abortion - just so you know” can be ordered by calling 01865 719418 or writing to FPA Sales Limited, Mail Order Department, PO Box 883, Oxford OX4 4NT.