HS2, the contentious rail project that will offer a high speed link from London to cities in the north of England, has been forced to deny claims that its trains are at serious risk of derailment when travelling at top speed.

Research commissioned by HS2 and completed last year by Prof Peter Woodward is believed to have found that the speeds proposed would create “critical track velocity effects” and “significant issues” with track instability.

Woodward is reported as saying that speeds as high as those planned by HS2 could cause “rapid deterioration of the track, ballast and sub-ballast, including possible derailment and ground failure”.

The £55.7bn high-speed rail project linking London to Birmingham and then to Manchester and Leeds will see trains operate at speeds of up to 360km/h, faster than any current operating speed in Europe.

No other country runs high-speed trains at more than 300km/h, which is now the accepted norm in China, France, Germany and Japan. Ministers have said it will improve the transport network and boost the economy, particularly in the north, but the scheme has run into fierce opposition on environmental and economic grounds.

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Woodward said the ballasted track of the kind to be used by HS2 “may not be able to adequately retain the track geometry” at the 360km/h line speed proposed, according to the Sunday Telegraph.

He said “embankment instability, particularly over poor soils … will generate significant issues during construction and operational running”. About 172km (107 miles) of the route, roughly a third of the total length, will run on embankments.

Woodward is said to have recommended massive ground stiffening and reportedly said that the track should be laid on a concrete slab. However, this would be more expensive and much noisier than ballast.

In its response, HS2 strongly rejected the reports and denied that there were any safety issues with its design. A spokesman said: “There are definitely no safety issues associated with the design of HS2. To suggest otherwise is wrong. On all issues, the programme will select the best possible and safest technical solution.”

Prof Andrew McNaughton, the technical director at HS2, said: “We have a world-class team of engineers including some of the most prominent in their field working on HS2. We also have shared experience from high-speed train services around the world built up over decades. HS2 is being designed and developed with safety as the key priority. Mitigation measures designed to cope with all phenomena occurring when trains travel at these speeds have been costed into the project.”

Last month, independent analysts said a small reduction in the top speed of HS2 trains would increase journey times by 4.5 minutes, but massively reduce carbon emissions and noise.

Research commissioned by objectors to the 117-mile HS2 line through the Chilterns shows that if trains were limited to 300km/h, rather than the proposed 360km/h, they could save hundreds of thousands of tonnes of CO2.

HS2 has launched two consultations on its environmental impact assessment and equality impact assessment, which ensures that a scheme does not discriminate against any disadvantaged or vulnerable group.