Following up on Richard's "Rubbish, Howard Jones" comment- This is indeed considered terrorism, and is often referenced as "single-issue terrorism". there have been at least 11 anti-abortion murders, the most visible have been the one resulting from Centennial Park Olympics bombing which also injured 111.

Obviously, before this incident, our UK friends had no awareness of the of the history--which, perhaps accounts for their slowness to accept that this crime was rooted in the religious-based anti-abortion movement.

From Wikipedia:

According to statistics gathered by the National Abortion Federation (NAF), an organization of abortion providers, since 1977 in the United States and Canada, there have been 17 attempted murders, 383 death threats, 153 incidents of assault or battery, 13 wounded, 100 butyric acid attacks, 373 physical invasions, 41 bombings, 655 anthrax threats,and 3 kidnappings committed against abortion providers...property crimes committed against abortion providers have included 41 bombings, 173 arsons, 91 attempted bombings or arsons, 619 bomb threats, 1630 incidents of trespassing, 1264 incidents of vandalism, and 100 attacks with butyric acid.The New York Times also cites over one hundred clinic bombings and incidents of arson, over three hundred invasions, and over four hundred incidents of vandalism between 1978 and 1993.