An attempt by anti-abortion campaigners to have the morning-after pill banned - which would also have undermined the use of most other forms of contraception - was categorically rejected by a high court judge yesterday.

Mr Justice Munby, giving judgment, told the court in the strongest possible terms that decisions on contraception must be left up to the individual. "I have to say that I cannot see that it is any part of the responsibilities of public authorities - let alone of the criminal law - to be telling adult people whether they can or cannot use contraceptive devices of the kind which I have been considering."

The judicial review was brought by the Society for the Protection of the Unborn Child (Spuc) against the Department of Health, the Family Planning Association and Schering, manufacturers of the morning-after pill.

In what amounted to a rebuke to Spuc, the judge made it clear that he felt the issue should not be decided in court. "It is, it seems to me, for individual men and women, acting in what they believe to be good conscience, applying those standards which they think appropriate, and in consultation with appropriate professional (and if they wish, spiritual) advisers, to decide whether or not to use IUDs [inter-uterine devices], the pill, the mini-pill and the morning-after pill. It is no business of government, judges or the law."

Government's responsibility was to ensure that medicines were safe and to offer guidance. "Beyond that, it seems to me, in this as in other areas of medical ethics, respect for the personal autonomy which our law has now come to recognise demands that the choice be left to the individual," he said.

Spuc sought the judicial review to try to prevent the morning-after pill - known by the brand name Levonelle - from being sold over the counter to women without a doctor's prescription.

It argued in court that the morning-after pill was not a contraceptive but an abortifacient because it does not prevent fertilisation but it does prevent a fertilised egg from implanting in the lining of the uterus. This, said Spuc, was a miscarriage as defined 140 years ago, in the Offences Against the Person Act 1861. If the court agreed that the morning-after pill was an abortifacient, then it was regulated by the Abortion Act 1967, and must not be available without the written consent of two doctors.

This argument had an enormous potential impact on most forms of contraception that have been used for decades by women. The IUD also prevents implantation of a fertilised egg, and although the main function of the mini-pill is to prevent fertilisation of the egg, it also thins the lining of the womb so that if an egg is fertilised, it will not implant.

Spuc claimed it was not pursuing other forms of contraception than the morning-after pill, but Mr Justice Munby yesterday said that what went for one also went for the others. "Whatever Spuc may say, these allegations of serious criminality which it makes extend to cover any form of birth control which may have the effect of discouraging a fertilised egg from implanting in the lining of the womb - that is to say, not merely the morning-after pill but also IUDs, the mini-pill and even the pill itself."

Spuc's legal argument was wrong, however, he found. The definition of "miscarriage" found in the 1861 act was not relevant - what mattered was the way miscarriage is defined today. A miscarriage in that sense occurs when a viable pregnancy - one in which a fertilised egg has implanted in the lining of the uterus - comes to an end.

Family planning organisations and those involved in the decision to make the morning-after pill available through pharmacies were delighted by the judgment. Anne Weymann, chief executive of the Family Planning Association, called Spuc's pursuit of a judicial review "a vexatious attack on women's reproductive rights and a dreadful waste of public and private time and money". The judge had confirmed that the morning-after pill did not cause an abortion.

Marshall Davies, president of the Royal Pharmaceutical Society of Great Britain, said: "This landmark judgment endorses the right of women to make their own choices about their method of contraception. It is also an important recognition of the professionalism of pharmacists, who will now continue to provide a highly valuable service."

· Special report on gender issues theguardian.com/gender