A leading abortion provider and pro-choice campaigners have said they feel "under siege" and at the mercy of a political "witch-hunt" after the government ordered an unannounced inspection of more than 250 clinics in England and claimed that as many as a fifth of them were pre-signing consent forms for terminations.

The health secretary, Andrew Lansley, ordered the Care Quality Commission to carry out spot checks on abortion clinics this week, saying afterwards he was "shocked and appalled" to learn of evidence that blank forms were allegedly being signed in anticipation of women seeking terminations.