The government today announced a review of risks to thousands of women from faulty breast implants fitted by a French company.
Health Secretary Andrew Lansley expressed concern that existing evidence about potential dangers was not reliable.
Around 40,000 women in Britain are believed to have had silicone implants made by Poly Implant Prothese (PIP), including hundreds who underwent reconstructive breast surgery through the NHS.
The French authorities shut down PIP last year after the company was found to be using cheaper industrial silicone. Paris has since recommended that women have the prosthetics removed because of fears over rupture.
However, the UK's Medicines and Healthcare products Regulatory Agency (MHRA) has previously indicated that its data suggests the risk of rupture is only 1%, rather than the 3.6% estimated by France. There is also no evidence of cancer links, and on that basis it has said removal is not necessary.
Speaking this morning, Mr Lansley said NHS Medical Director, Professor Sir Bruce Keogh, would now be carrying out a review of the situation.
The MHRA will also be conducting an audit of its evidence to resolve concerns about the "content and quality of the data that cosmetic surgery providers are sharing with the regulator".
"We are doing everything we can to ensure that women with these implants get the best possible advice," Mr Lansley said.
"So far, all the evidence from around the world suggests that women should not be worried and that there have not been abnormal levels of problems reported with these implants. But if any woman is worried, then they should contact their surgeon or GP.
"We have, however, received data from an organisation yesterday that was not previously acknowledged or communicated to the MHRA.
"The validity of this data still requires full assessment and evaluation, so I have asked Professor Sir Bruce Keogh to lead an urgent investigation so that we can establish exactly what has happened and whether we need to improve the regulatory regime.
"I want to reassure women that if any new data comes to light which calls into question the safety of these implants, we will act swiftly to help them. Our top priority is making sure that women get the correct advice so that they are kept safe."