The fertility industry regulator yesterday took the unprecedented step of obtaining a warrant to inspect the records of Britain's most successful IVF clinic on the day a TV programme questioned its methods.

Police officers accompanied officials from the Human Fertilisation and Embryology Authority (HFEA) to two London clinics run by Mohamed Taranissi. One of his clinics, the Assisted Reproduction and Gynaecology Centre, has the highest success record in the country, with a 59% pregnancy rate among women under 35.

Yesterday Angela McNabb, chief executive of the HFEA, said the police had been called in because of the frustrations of the authority in attempting to access Mr Taranissi's paperwork.

Almost every IVF clinic in the UK fully cooperated with the inspection and regulatory process, she said. "But we have faced unique difficulties with the clinics run by Mr Mohamed Taranissi." The HFEA had asked a court for the warrant.

She said the action was not connected to last night's Panorama programme, which claimed that Mr Taranissi's clinics were offering women expensive, unnecessary and unproven treatments.

Mr Taranissi said yesterday he had fully cooperated with the inspection team and would continue to do so.