LONDON (AP) -- A top British medical expert says faulty French-made breast implants do not pose any long-term health problems to women even if they rupture.

The implants made by the now-defunct French company Poly Implant Prothese were pulled from the market last year in several countries amid fears they could rupture and leak silicone into the body.

Around 47,000 British women are believed to have been given the PIP implants, which were filled with industrial, rather than medical-grade, silicon. The government asked Bruce Keogh, medical director of Britain's National Health Service, to launch an investigation last December to assess what threat, if any, the implants posed to the woman's health.

Keogh studied the 240,000 implants of differing brands that have been given to 130,000 women in England and looked at data from other countries including France and Australia. On Monday, he said that studies showed the PIP implants were more likely to rupture than other brands, but do not pose a long-term risk to the health of the women who have them.

He said repeated tests in several countries showed that the implants are not toxic.

"Therefore we do not believe they are a threat to the long-term health of women who have PIP implants," he said. "We have, however, found that these implants are substandard when compared to other implants and that they are more likely to rupture."

Countries have differed in how they treat women with the PIP implants.

France has said it will pay for some 30,000 French women to have their implants removed.

The U.K. government has agreed to remove any implants put in by the National Health Service, such as those for cancer patients, but said women who had the surgery done privately have to have those clinics remove the implants.

Australia's medical watchdog, however, said health officials have found no evidence that the PIP implants had an increased risk of rupture in Australian women.

In the Czech Republic -- where the implants were banned in 2010 -- the country's health ministry said it would negotiate with the country's health insurers on how to cover the cost of removals.

Keogh said any woman in the UK who had possible symptoms of a rupture, such as tenderness, soreness or lumpiness, should first see her family doctor who would then refer her to a specialist.

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