Spokesperson for the Be Here for Me Campaign, Clare Carberry, told Premier's News Hour: "We are very surprised, very dismayed, it's an absolutely momentous ruling. This is the first time since the 16th century, I believe, normal prayer has been made criminal in the UK."
Ealing Council was the first in the country to create a 100-metre protest-free "buffer zone" outside a Marie Stopes clinic in the west London borough.
Mr Justice Turner decided to allow the ban after a Christian mother challenged it. He said the council was "entitled" to conclude it was a "necessary step in a democratic society".
Carberry believes the judge's decision has huge implications for Christianity in the UK.
"A Christian may not pray in that very wide area on that particular road," she said. "You also may not make any expression of opinions regarding abortion and you may not offer help for women who are in need. For a Christian this is particularly significant because practice is just as important at theory for us.
Ealing Council enforced the buffer zone following what is described as protests that intimidated, distressed and harassed women using the abortion clinic.
However, Carberry said women were not protesting but rather holding prayer vigils and offering the clinic's patients information about alternatives to abortion.
"We don't describe what we're doing as a protest. It really is, a critical charitable outreach to women who are under incredible pressure to have abortions that they do not want, and we know that there are many of these women," she said.
"The laws are already in place to deal with the absolutely horrendous allegations. We would be calling the police ourselves if we saw this kind of behaviour. The group that has been banned are absolutely innocent."
Carberry said since the buffer zone was enforced, pro-life campaigners have extremely limited access to the clinic's patients.
Ealing Council leader Julian Bell said: "We are delighted that Mr Justice Turner has emphatically upheld our PSPO at Mattock Lane in full with no parts quashed.
"This sends a clear message to those that have denied that there is evidence of unacceptable behaviour having a detrimental impact on people in this area, that there was a problem and action needed to be taken.
"The harassment and intimidation of local residents and those accessing legally available medical services was totally unacceptable and 'the feelings of intrusion' was clearly having a negative impact.
"Since the safe zone was implemented in April, we have seen a dramatic reduction in anti-social behaviour, confirming to us that we were right to take this action in the interest of those people living in the locality of Mattock Lane, and for those who visit the area."
Listen to Clare Carberry speaking with Premier's Tola Mbakwe here:
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