The material commonly used in vaginal mesh implants starts to degrade within 60 days of being implanted in the pelvis, according to a new study.

Researchers also found particles of polypropylene, a type of thermoplastic, in the tissue surrounding implant sites.

Campaigners called for 'immediate action' from the medical community and regulatory bodies based on the findings 'to ensure that no more lives are shattered by this dangerous product'.

Transvaginal mesh (TVM) implants - made from synthetic materials such as polypropylene - have been used to treat pelvic organ prolapse and stress urinary incontinence, but can cause debilitating harm to some women.

Side effects have included infection, pelvic pain, difficulty urinating, pain during sex, and incontinence.

The NHS restricted its use of TVM implants in 2018 and they are now used only as a last resort through a high-vigilance programme of restricted practice.

The study by scientists at the University of Sheffield looked at polypropylene mesh implanted in sheep, which share a similar pelvic anatomy to women.

They found fibres started to degrade within 60 days, becoming stiffer and showing signs of oxidation, a process which increased over time.

Researchers also discovered polypropylene particles in the tissue around the implantation site.

The concentration of these particles was 10 times higher after 180 days than at 60 days, according to the study.

Sheila MacNeil, emeritus professor of biomaterials and tissue engineering at the University of Sheffield, said: 'This research provides objective physical evidence that this material does not cope well with implantation in the pelvis.

'This is crucial because it is imperative that we develop new and better materials for the many thousands of patients suffering from stress urinary incontinence and pelvic organ prolapse.

'We now know how to critically assess any issues in new materials before they are implanted in women.

'It is vital to have tests to detect potential failures in materials, rather than trialling untested materials in patients.'

The research, published in the Journal of the Mechanical Behaviour of Biomedical Materials, suggests polypropylene surgical mesh 'was not tested for suitability at the site of implantation' but rather 'an assumption was made based on the success of polypropylene mesh used to treat abdominal hernias that the same mesh would work equally well in the pelvic floor'.

It comes after more than 100 women in England with complications from vaginal mesh implants were given payouts as part of a group settlement.

Study lead Dr Nicholas Farr, research fellow at the University of Sheffield, added: 'Our results provide strong evidence of the instability of polypropylene and offer new insights into the mechanisms that contribute to its degradation within the body.

'While the recent monetary compensation for affected patients is undoubtedly a welcome development, there remains an urgent clinical need for safer materials to address pelvic organ prolapse.

'It is my hope that the insights from this study will be recognised by current, and future, mesh manufacturers and will contribute to the ongoing development of safer alternatives.'

Kath Sansom, founder of the support group Sling The Mesh, which has almost 11,000 members around the world, said the findings 'provide yet more damning evidence about the dangers of polypropylene mesh'.

'The mesh-injured community have endured debilitating complications, unaware that the plastic material implanted in their bodies is not fit for purpose and could degrade so quickly,' she said.

'This study confirms what many of us have suspected - that the mesh becomes unstable, causing harm that is irreversible.

'It's critical that this new research is used to drive immediate changes in medical practice - including the need for surgeons to re-learn traditional skills using trusted native tissue methods to fix prolapse and stress incontinence - without plastic mesh.

'Patients deserve better. We must prevent further suffering.'

Ms Samson, a former journalist and mother-of-two from Cambridgeshire, added: 'The mesh community trusted that their treatment was safe but have been left to deal with chronic pain, infections, loss of mobility, autoimmune disease and even organ damage and organ removal where the plastic material has turned brittle, acting like an internal knife cutting into tissues and nerves,' she added.

'It's completely unacceptable that so many were not informed of these risks.

'The medical community and regulatory bodies must take immediate action based on this research to ensure that no more lives are shattered by this dangerous product.'

Dr Alison Cave, chief safety officer at the Medicines and Healthcare products Regulatory Agency (MHRA), said: 'Patient safety is our top priority and the use of surgical mesh to treat stress urinary incontinence and pelvic organ prolapse has been subject to restrictions since July 10 2018.

'Exceptions are made in cases where this type of mesh may be the only treatment option that is right for a woman.

'However, it should only be used for carefully selected patients who have been informed of, and understand, the benefits and risks, and where all other treatment options have been explored.'