Earlier this month a man was charged with the murder of a doctor at a Rescue America protest in Florida. Group supporters regularly brandish pictures of aborted foetuses at women entering clinics, scream abuse at staff and storm operating theatres.
The London headquarters of the International Planned Parenthood Federation, an umbrella organisation for contraception, sex education and abortion services in 140 countries, has been warned by its US member clinics to be prepared for acid attacks and fire bombs.
The federation has seen an invitation from Fr James Morrow, a radical Scottish anti-abortionist, to 'picket and rescue babies', at the federation's offices, starting on Tuesday. The invitation calls the federation 'the greatest enemy to the human race after its ally, Satan'.
Yesterday, at Fr Morrow's Braemar headquarters, Sylvia Green, a follower, said the priest was in London to meet Don Treshman, Rescue America's leader, and other anti-abortionists from Russia and Europe.
Last night Frances Perrow, federation spokeswoman, said an eight-strong 'advance party' was outside the HQ taking pictures of staff.
Ms Perrow said she had received abusive calls accusing her of being a Nazi involved in selective breeding. She said: 'What is worrying is that these people do not want a rational discussion. The caller insisted it was a simple choice between God and love and Hitler and death.'
The visit has split anti-abortion organisations in Britain. Life, a mainstream anti-abortion group, dissociated itself from Rescue America, while the Society for the Protection of the Unborn Child (Spuc) refused to condemn the US group's tactics.
Keith Davies, Life's spokesman, said militant action was damaging the anti-abortion lobby's image in Britain. He said: 'We will definitely not be taking part in any picket. We told our members two years ago that they could not demonstrate with militants under the name of Life.'
But Paul Tully, spokesman for Spuc, said the media had been biased over Rescue America's activities, ignoring violence against protesters. He added: 'We do not condemn other groups and we will not recommend our members not to take part in Rescue America's protests. It is a free country. How are we to stop them?'
Leonora Lloyd, spokeswoman for the 'pro-choice' National Abortion Campaign, said that despite tactical differences, Life, Spuc and Rescue America were basically the same. 'They all think they know better than the women concerned.'