A new high speed rail line in the UK may produce only very modest environmental benefits, despite the supposed green credentials often cited by politicians, say the RAC Foundation.

Building a high speed line linking London to the North of England and Scotland is also likely not just to take people out of their cars and off planes, but generate a lot of new travel - as much as a fifth of passenger trips could be ‘induced'.

And not enough work has yet been done on assessing whether the tens of billions of pounds being earmarked for high speed rail (HSR) would be better spent on other areas of transport.

These are amongst the findings of ‘The Case for High Speed Rail: A review of recent evidence', by Professor John Preston, commissioned by the RAC Foundation and published today.

Stephen Glaister, director of the RAC Foundation, said: "We would question the wisdom of any government backing a scheme which encourages more people to travel very long distances at a time when the objective must be to find alternatives to movement, such as home working and shorter commutes.”