Midwives have reacted with fury after the chief executive of their union reportedly backed a campaign to scrap the abortion time limit without consulting its members.
Royal College of Midwives (RCM) chief executive Cathy Warwick also holds a top position at a charity advocating the law change and has been told by MPs to consider her position over the potential conflict of interest.
One Tory member of a Parliamentary health committee said the conflict was clear, branding it "pretty disgusting".
Professor Warwick chairs the board of trustees at the British Pregnancy Advisory Service (BPAS), which assists 65,000 women a year with birth control and has called for abortions to be removed from criminal law.
Under current laws, a woman can be liable to life imprisonment if she terminates her pregnancy beyond 24 weeks without medical legal authorisation.
In February the professor, in her capacity as head of the RCM, said the campaign had the union's full support as she called for the legal limit to be "relegated to history".
A report by the Daily Mail said RCM members were not consulted on the move, a decision branded as "shocking" by one midwife.
Judith Smyth, a midwife from Northern Ireland, told the newspaper: "Anyone advocating allowing abortion up to birth, I think is so sad and tragic, but to have my own representative body coming out in support of this extreme view is very disappointing.
"'I know she's our chief, but there is clearly a conflict of interest. On something as big as this, she should have consulted us."
An RCM spokesman told the newspaper Professor Warwick had not consulted the union's members on the issue, but said its constitution allowed the board to "set our strategic objectives" and the union had to advocate for choice in all aspects of women's care.
The spokesman added: "The RCM is not for or against abortion. It is for women, and respecting their choices about their bodies. NHS policy is explicit that high-quality maternity services include respecting women's right to make reproductive choices.
"The RCM's stance on decriminalisation of abortion is compatible with this."
Michelle Viney, who has worked as a midwife for 15 years, questioned why the RCM thought it did not have to put the issue to its members.
She said: "I financially support it [the college], but I wouldn't want to be paying a fee towards an organisation which is going to be campaigning for something which, morally, I 100% disagree with."
Several MPs criticised Professor Warwick's decision to back the BPAS campaign, including Andrew Percy, a Conservative member of the House of Commons Health Select Committee.
He told the Daily Mail: "It is clearly a conflict of interest if she is doing the two roles. It's pretty disgusting. She represents midwives, many of whom will absolutely not agree with this campaign, and she should think very hard about whether or not her position is sustainable."
Labour MP Robert Fellow said he was "utterly and completely appalled by this abhorrent proposal".
He told the Daily Mail: "This wasn't a minor policy shift by the Royal College of Midwives, it was a fundamental change and the reason they didn't ask their members is because they knew they wouldn't get it past them.
"It is unacceptable that the RMC is led by someone so closely aligned to the biggest provider of abortions."
Democratic Unionist MP Jim Shannon said he would put the issue to Jeremy Hunt in Parliament later this week.
He told the newspaper: "I will ask the Secretary of State for Health what discussions he has had, or will have, with the RCM and BPAS.
"My concern is that scrapping the 24-week cut-off would be absolutely disgraceful.
"I would have thought the RCM should be protecting unborn life. Its chief executive has this dual position and many people would say you can't have that."