Around 7,000 more women in the UK have received potentially faulty PIP breast implants than previously thought, the government revealed on Thursday afternoon.

The revised figures mean that the total number of women in England and Wales potentially affected stands at nearly 50,000. Most of those had their implants put in by private clinics, some of whom have refused to foot the bill to have the implants replaced.

Women in England who had PIP implants put in by the NHS are entitled to have them removed and replaced free of charge, but the government will only pay for the removal of implants fitted by a private clinic.

Hundreds of thousands of women have been affected by the scandal - in which implants consisting of industrial-grade silicone were used instead of the more hardy medical-grade. These industrial silicone implants are considered by many countries to be at increased risk of rupture.

The boss of the French firm which made the substandard implants is currently languishing in a French jail awaiting his trial.

Health Secretary Andrew Lansley said the NHS were committed to supporting women, saying: "Our commitment is to ensure support for all women from the NHS if needed; we will continue to press for the same standard of care or redress from private providers."

In a statement on Thursday the Department of Health said:

French authorities had previously advised that only PiP breast implants that were used after 2001 may have been made with unauthorised silicone gel.

Following an investigation by the UK regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), the French authorities have this week reported that PiP implants made before 2001 may also contain unauthorised silicone gel.

This means an extra 7,000 women, who had PiP implants before 2001, could be affected. About one in five breast implants need replacing within ten years, whatever the make, so it is unlikely that all these 7,000 women still have the same PiP implants.

The independent expert group – led by the NHS Medical Director Professor Sir Bruce Keogh – continues to advise that there is not enough evidence to recommend routine removal of PiP breast implants given that this would mean many women having to have surgery.