Bucks Berks and Oxon Wildlife Trust (BOWT) has launched a legal challenge against the government’s Oxford to Cambridge Expressway proposal and associated housing development.
A statement from BOWT said: "This is because we believe Highways England and the Department for Transport did not follow due process when selecting the route for the development, and that their failure to do so has put our local wildlife in grave danger.
"The government selected this route against our advice.
"Earlier in the year, we warned them in a closed consultation that 'Corridor B' would have devastating impacts on wildlife.
"We also emphasised that a route should not be selected without first undertaking a Strategic Environmental Assessment, which we believed they were required to do under EU law."
The Expressway is a new road proposed by the government that will link Oxford and Cambridge, via Milton Keynes.
The project also includes a proposed ‘Growth Corridor’ that will see the building of one million new homes between Oxford and Cambridge by 2050.
Earlier this year, Highways England proposed three broad routes, or ‘corridors’, for the Expressway and Growth Corridor. On September 12, the government announced that they had selected ‘Corridor B’ to accommodate the Expressway and associated housing.
The trust added: "Ancient floodplain meadows on the River Ray and River Thames where rare wading birds breed; forests home to one of the last populations of Bechstein’s bat in Britain; old hedgerows that support rare black and brown hairstreak butterflies – all these are now at risk because the government failed to consider the environment when making their decision.
"We cannot simply stand by while these precious places are destroyed. It is for this reason that today we started the process of challenging the government by Judicial Review."