Pro-lifers have expressed disappointment over the Mayor of London's support for buffer zones around abortion clinics.
Sadiq Khan outlined his support in a recent letter sent to the Abortion Rights campaign group after it raised concerns about the March for Life UK in London last week.
In the letter, Mr Khan welcomed the countermarch held by Abortion Rights during the March for Life and said that the "right" to have an abortion "must be safeguarded".
He said he was concerned about the "unacceptable promotion of harassment" against abortion providers and those using their services, saying that women should be able to access them without fear.
He told the pro-choice group that he "fully supported" the recent imposition of a buffer zone around an abortion clinic in Ealing preventing pro-lifers from coming within 100 metres of the building and said he was "deeply disappointed" that the Government had refused to implement the measure nationwide.
"Of course, I recognise that some people passionately hold different views and they should be allowed to voice them if they wish," he said.
"But this must be balanced by the recognition that women have the right to get medical advice and to seek treatment in confidence, free from abuse."
Pro-life campaign group Be Here For Me, which offers support outside abortion clinics, said its work was peaceful and that members of the pro-choice movement "aggressively bully" those offering help to women thinking about an abortion.
The group accused the mayor of being "indifferent" to women considering an abortion and their "poverty of choice".
"A strange position for a representitive of the Labour party to be in. For the mayor it seems that one choice only is good enough for them: abortion. But of course one choice is no choice at all," it said.
"Some of the women helped by the pro lifers are literally facing destitution. Some are under intense social pressure. Many have wept lonely prayers begging God to send someone to help them."
It added: "We know the excruciating pressures they are under to end their pregnancies, not as a free choice but as a duty. The Mayor of London regrets that there is not yet a national ban on the kind of help we offer to them. How is that 'pro choice'?"