Doctors are breaking the law if they “pre-sign” abortion consent forms, the government has said.
Spot checks at more than 250 abortion clinics this week found evidence of blank forms being signed in anticipation of patients seeking a termination.
The law states that, except in emergencies, two doctors must agree for a woman to have an abortion.
Although doctors do not have to see the woman in person, they must certify that they are aware of her circumstances and why she wants to go ahead with the procedure.
Nurse, counsellors and other healthcare professionals can assess the woman before the forms are signed.
The inspections in England by officials from the Care Quality Commission were ordered by Andrew Lansley.
Of more than 250 clinics investigated so far, it is thought 15 to 20 per cent may be breaking the law.
The clinics included those run by the British Pregnancy Advisory Service (BPAS), Marie Stopes, the NHS and private firms.
Marie Stopes said none of its 19 units were found to have breached the rules, while BPAS said that, to the best of its knowledge, none of its clinics were involved.
Mr Lansley said: “I am shocked and appalled to learn that some clinics - which look after women in what are often difficult circumstances - may be allowing doctors to pre-sign abortion certificates.
“This is contrary to the spirit and the letter of the Abortion Act.
“The rules in the Abortion Act are there for a reason - to ensure there are safeguards for women before an abortion can be carried out.
“To protect women the right checks and balances must be in place.
“The CQC has agreed to undertake unannounced inspections to identify the scale of this problem.
“And we will set up a special team comprising of all the necessary regulators and the Department to look at how we stamp out bad practice in abortion clinics.”
The news comes after a Daily Telegraph investigation last month uncovered allegations that doctors at three clinics had agreed to terminations based on the sex of the baby.