Thousands of high street chemists are to be told they may be allowed to sell the morning-after pill without a prescription to girls under 16.

The Royal Pharmaceutical Society (RPS) said last night that the controversial guidance issued by the Department of Health (DoH) last week, which said girls under 16 should have access to confidential advice on contraception or having an abortion without parental consent, could also apply to the supply of over-the-counter emergency contraception.

The RPS, the regulatory body for Britain's community pharmacists, said that it would issue revised guidance in the autumn to pharmacists drawing on the department's advice last week, which infuriated anti-abortion groups.

It was thought that it would be illegal to sell the morning-after pill as an over-the-counter medicine to girls under the legal age of consent at 16.

The ministerial guidance to doctors last week reinforced the so-called Gillick judgment in the House of Lords in 1986 which allowed contraceptive advice to be given without parental consent, provided it was on the basis of informed choice, by a doctor discussing the clinical implications with the patient. For the first time, the guidance last week made it clear that the judgment also applied to abortions.

"Pharmacists have a duty to the care of patients of all ages, and there is an ability to provide contraception services to under- 16s following the Gillick guidelines and the guidelines [by the DoH] which reinforce that," said an RPS spokesman. Pharmacists also face a dilemma because the morning-after pill is only effective if it is taken within 72 hours of unprotected sex. Within a year of the morning-after pill being legalised as an over-the-counter medicine in three inner-city pilot areas, it was found that 4 per cent of users were girls under 16.

"It is a grey area," the spokesman said.

Ministers are to be pressed by a senior Labour MP to clarify the law. Howard Stoate, Labour chairman of the all-party parliamentary pharmacy group, said that the current law on the morning-after pill needed clarifying to ensure that girls facing an unwanted pregnancy could also obtain emergency contraception.

General practitioners are permitted to prescribe the morning-after pill to girls under 16 but the licence for the sale of the drug over the counter in community pharmacists is restricted to girls and women of 16 and over.

"I am saying it is illogical and I will be asking ministers to review the law," Mr Stoate said. "You cannot get the morning-after pill under the age of 16 from the chemist over the counter, but if you go to your GP you can get a prescription for it.

"I have accused the makers of wimping out by restricting their licence."

The drug may be legally prescribe to girls under 16 in pilot areas where the Government has extended prescribing to community pharmacists.