Women in England will only be able to access abortion tablets online illegally because ministers are ending the “pills by post” trial, MPs have been told before a crucial Commons vote on the scheme.

Medical groups, pro-choice campaigners and women’s organisations say the government’s decision to end the two-year experiment will lead to those seeking to end a termination breaking the law and risking criminal charges.

The Department of Health and Social Care sparked an outcry last month when it announced that it was extending the trial until the end of August but then scrapping it.

The policy was brought in as a temporary measure when Covid-19 hit in spring 2020. It is being axed even though more than 150,000 women have used it since then. It has proved popular with women and has been hailed as “the single biggest positive revolution in abortion rights in the UK since the 1967 Abortion Act”.

Under it, women no longer have to visit a hospital or clinic to take the first of two pills used to induce an abortion within the first 10 weeks of pregnancy. Instead, they are sent both tablets to take at home. Wales has made the service permanent and Scotland looks likely to do the same.

In a briefing to MPs, however, an alliance of medical and women’s groups as well as abortion providers said: “Banning telemedicine would force vulnerable women who cannot access in-clinic care back to unregulated online options, risking criminalisation.” The number of women who resorted to buying pills online fell by 88% when the trial began.

MPs will help to decide the future of the scheme when they vote on Wednesday on an amendment to the health and social care bill recently passed by the House of Lords. It seeks to overturn the ending of pills by post in September and make the scheme permanent.

Pro-choice campaigners’ hopes of overturning the government’s policy have been boosted by MPs being given a free vote, in line with parliamentary tradition on abortion, which is seen as a matter of conscience.

“Telemedicine for early medical abortion has been a success story of the pandemic, and the removal of this service would be an infringement on women’s rights to access the healthcare they deserve”, said Dr Edward Morris, the president of the Royal College of Obstetricians and Gynaecologists.

“With the UK government due to publish the women’s health strategy shortly, it would be completely inconsistent for them to choose to stop listening to women’s views on this vital area of their healthcare.”

Some Tory MPs are backing the move to make pills by post permanent. They include former ministers Caroline Nokes, Sir Peter Bottomley and Crispin Blunt. Scraping the scheme is “a grave misjudgment” that is inconsistent with the government’s commitment to gender equality, they say.

Louise Cudden, the UK advocacy and public affairs adviser at MSI Reproductive Choices, a global charity that provided 60,000 abortions in England last year, said: “From the World Health Organization, to the US Food and Drug Administration, to the government in Wales, there is a consensus that abortion pills can be safely taken at home. However, in England that choice is denied.”

Campaigners fear that vulnerable women, including those experiencing domestic abuse or who have a controlling partner, will be denied the chance to have a termination unless ministers do a U-turn.

“Before the pandemic we spoke every day to women who faced insurmountable barriers to accessing our help in a clinic, and we were powerless to help them,” said Clare Murphy, the chief executive of BPAS, another abortion provider.

“We have shown we can help these women, and it would be an absolute travesty if that service was withdrawn and women forced again to turn to organisations like Women on Web to meet their reproductive healthcare needs”.

The Department of Health and Social Care said: “We recognise this is a highly sensitive area. Abortion is an issue on which the government adopts a free vote. Ensuring women can access health services in a safe, secure way remains our priority.”