Women embarking on the festive party season in Britain are being invited to stock up on free supplies of the morning-after pill.
The British Pregnancy Advisory Service (BPAS) has launched a service where women can request the pill over the phone and get it delivered free of charge to their home.
The charity says the move will help women prevent unwanted pregnancy over the Christmas and New Year period.
The pro-life charity Life said the BPAS scheme meant getting the morning-after pill in the UK was now as easy as dialling for a pizza.
Spokeswoman Michaela Aston added there was no evidence the morning-after pill reduced unintended pregnancy rates.
"In fact, if a woman has the morning-after pill at home 'just in case' she may be more likely to engage in risky sexual behaviour than she would normally - particularly over the festive period with the associated increase in alcohol consumption.
"What a sad state of affairs that over Christmas BPAS is anticipating and encouraging unwise sexual behaviour by enabling people to stockpile the morning-after pill."
She said the charity had "serious concerns about the health risks associated with the morning-after pill, especially as a woman phoning up will not be physically examined or able to discuss the matter with her own GP.
"This pill contains a powerful cocktail of drugs, strong enough to stop ovulation.
"It is, in effect, a super pill - many, many times stronger than the ordinary contraceptive pill and has a significant impact on women's bodies."
The morning-after pill is most effective if taken as soon as possible after unprotected sex, preferably within 12 hours.
But it can be taken for up to 72 hours after intercourse.
BPAS said women face barriers obtaining the pill, including not being able to get appointments, some health workers refusing to provide it and the £25 (€29.23) cost if bought direct from a pharmacist.
It says these issues are made worse at Christmas, when chemists and surgeries may be closed.
Women wishing to obtain the pill in advance can fill out a form at www.santacomes.org.
They leave their details and a time at which they can be called in privacy by a specially trained nurse.
In a 15-minute consultation, the nurse will assess the age of the patient and ensure the pill is not being requested for immediate use.
Women will also be told how to take the pill and what to expect.
The pill will then be despatched with condoms and "advice literature" to the woman's home address.
A spokeswoman for BPAS said nurses are trained in spotting under-16s, who would be referred to a BPAS centre for a face-to-face consultation or another appropriate venue.
She said: "Women will be asked to put their date of birth on the form. We are aware that some people will not be completely honest about their age."
But she said the charity did not envisage this being a widespread problem.
Tracey Forsyth, BPAS lead contraception nurse, said: "The morning-after pill can be taken up to 72 hours after unprotected sex, but the sooner it is taken the better - and having it at home means you are much more likely to take it as soon as you need it.
"Sometimes women worry that requesting the pill in advance makes it look like you are planning on taking chances.
"In fact, the opposite is true - making sure you have a back-up to help prevent an unwanted pregnancy is making sure nothing is left to chance.
"It's a particularly good idea if you are relying on condoms. When you contact us we'll also be able to answer any questions you have about sexual health and contraception, but haven't perhaps found the time or place to ask."
Ann Furedi, BPAS chief executive, said: "We are as committed to helping women avoid the need for abortion as we are to providing first-class abortion care.
"We know women often do not take the morning-after pill after unprotected sex.
"They may not think their risk of pregnancy is high and the cost, inconvenience or embarrassment of obtaining it may put them off.
"We hope being able to access it in advance over the phone for free will encourage more women to have one at home, just in case."
The service will be available while stocks last throughout December.
Figures released in May showed a slight overall rise in the number of abortions carried out.
Some 189,574 abortions were performed in 2010, up 0.3% on the 189,100 in 2009 and 8% more than in 2000 (175,542).
These abortions were to women living in England and Wales. Another 6,535 were to non-residents.
Half of abortions (49%) in 2010 were to women with partners while 26% were to single women and 16% of abortions occurred within marriage.
Some 3,718 were to girls under 16 (slightly down on the previous year), 12,742 were to those aged 16 and 17, and 21,809 were to girls aged 18 and 19.
Some 27,046 abortions were among women aged 35 and over.
Overall, most abortions (77%) took place before 10 weeks' gestation.
Health Secretary Andrew Lansley said: "Emergency contraception is intended to be exactly that - for emergencies not everyday use.
"Ideally, it would be better for it to be made available in person, which would mean any decisions were taken with the benefit of face-to-face advice.
"Women should be encouraged to use long-acting reversible contraception rather than emergency contraception."
A spokeswoman for BPAS said: "We are very happy for under-16s to contact us with any questions they may have, although before dispensing the pill we would arrange for them to come into one of our centres or refer them to a local provider where they can talk with someone face-to-face."