An increasing number of doctors are refusing to carry out abortions, leading to a crisis in NHS services, experts have warned.
Many doctors are opting out of providing abortions
The Royal College of Obstetricians and Gynaecologists says there has been a big rise in the number of doctors who are "conscientious objectors".
About 190,000 abortions take place in England and Wales annually.
The NHS pays for four out of five - but half of these are carried out by private sector providers.
This is double the proportion performed in the private sector 10 years ago.
Abortion is legal in Britain up to 24 weeks, however it can occur later if doctors believe the baby has a severe disability or if the mother's life is at risk.
Experts say the decline in the number of NHS doctors willing to perform abortions has also declined because they are able to "pick and choose" the areas they train and specialise in - and very few opt to carry out terminations when they can choose other areas such as fertility medicine.
Kate Guthrie, head of abortion services in Hull and a spokeswoman for the RCOG, told BBC Radio 4's Today programme: "We have always had conscientious objectors, but more doctors now are just wanting to something different and don't see abortion care as attractive."
But she said it was a necessary service.
"The Abortion Act came in because women were prepared to do anything rather than have unplanned pregnancies. Nothing has changed.
"If abortions are not available safely, women will turn to unsafe ways of procuring abortion."
She suggested a solution to the current crisis might be to increase the involvement of nurses in providing abortion.
Ann Furedi, of the British Pregnancy Advisory Service, which is a leading provider of abortions, said: "It is increasingly difficult to recruit doctors to abortion services.
"It is the case, that within five to seven years, a woman's ability to get an abortion will be more shaped by the service's ability to provide them rather than the state of the law."
She said doctors failed to realise how essential the abortion service was.
But Josephine Quintavalle, of the anti-abortion group Alive and Kicking, said: "We welcome this development.
"There is a sensitivity in this country that there are too many abortions, and this obviously will impact on doctors.
"We should be working together to make abortions rare."
And Julia Millington of the ProLife Alliance said: "We have been hearing for some time now that young doctors, in particular, do not want to work in this field.
"Those choosing to go into medicine presumably do so because they want to cure sickness and disease not end the lives of innocent human beings."
The Department of Health said it was aware a minority of NHS doctors chose to opt out of providing abortions, but added this did not prevent women obtaining a termination.
It added that a "stable" number of abortions was being performed each year, and that the number of terminations performed before the 10th week of pregnancy had increased from 51% in 2002 to 64%.