The British Pregnancy Advisory Service (BPAS) is setting up the scheme, which it says will help prevent unwanted pregnancies.

The BBC's Lucy Atherton: "One dose for the price of �10"

But the move has been criticised by pro-life and conservative groups, who argue that it could encourage teenage girls to have casual sex.

Until now, the morning-after pill has been available only on prescription to women who attend clinics or go to their GP within three days of unprotected sex.

A spokeswoman for BPAS, Ann Furedi, said that from next Friday, women would be able to ring an action line and book an appointment to see a doctor at their local BPAS branch.

"Provided there are no medical reasons against it she will be able to obtain a packet of emergency contraceptive pills to be used in cases of emergency," she said.

'A second chance'

Ms Furedi said the service, which will cost �10, had been launched after research conducted by the World Health Organisation showed the morning-after pill was 50% more effective if taken within 12 hours of having unprotected sex.

She said many working women would find it difficult to get an appointment to see their GP that quickly.

"We are concerned about unwanted pregnancies, and emergency contraception has a part to play because it gives women a second chance.

"What we are saying is that women can be responsible and protect themselves against unwanted pregnancy, in the same way that if a woman knows she might get cystitis she keeps a cystitis treatment at home, or if she is prone to headaches she keeps some aspirin in her cupboard."

Ms Furedi rejected arguments that the service could encourage women to have unprotected sex.

"If you have a fire extinguisher in your home nobody argues that it causes you to set your house on fire," she said.

"The fact people have access to emergency contraception doesn't cause people to have unprotected sex."

'Wrong signals'

But the director of Family and Youth Concern, Valerie Riches, said the scheme sent the wrong signals to teenage girls.

"It is saying that you can have casual sex and it might cost you �10 but you can bail yourself out," she said.

Paul Tully, of the Society for the Protection of Unborn Children, said: "The morning-after pill is available only on prescription and we would have very serious concerns for the health implications of women holding their own supply.

"It also shows a disregard for the right to life of the unborn child and contempt for the health of women and young girls who may be provided with drugs."