At least 150 footpaths are under threat from plans to build England’s high-speed railway between London and Birmingham.
The Ramblers said the proposed route would either bisect or obliterate a large number of paths and risk damaging 10 sites of special scientific interest.
In Buckinghamshire alone, 56 paths would need diverting or altering by the building of bridges and tunnels.
Fourteen of the 20 affected rights of way in the Chilterns Area of Outstanding Natural Beauty risk being lost permanently and seven Oxfordshire paths will be crossed by the HS2 route.
The campaigning charity welcomed the House of Commons Select Committee on Transport report which, it said, outlined environmental gaps in the Government’s business plan for HS2.
But the threat to walking routes was not being acknowledged, the Ramblers said.
Campaigns officer Rachel Alcock said: “Footpaths need to be accounted for now, in advance planning stages and the current potential impact from HS2 viewed as disruption to an entire network of public access to the countryside.
“If they are neglected and left to be dealt with case by case during the planning process, these footpaths will be at risk from being scrapped from our maps forever.
“What this means is not only an entire network of paths being shut down, but access to the countryside that surrounds these footpaths being cut off for good.”
The Ramblers said they do not object to High Speed Rail in principle, but their concern is that HS2 proposals have implications for footpaths and walkers that have not yet been analysed and there has been no guidance provided on how footpaths will be addressed.
Ms Alcock added: “We will continue to campaign vigorously to reduce the effects on the rights of way network, on footpaths and the surrounding countryside.
“The select committee report has only strengthened this position by acknowledging the current lack of clarity surrounding the environmental impact of HS2.
“The Ramblers agree that anything less than a full environmental impact assessment, including the impact on footpaths, would be insufficient and irresponsible. We urge the Government to tackle this issue with eyes wide open, to ensure that HS2 takes the best track possible for all.”
The select committee also said the Government should ‘desist from disparaging opponents of high speed rail as Nimbys [Not in my Back Yard]’. Both sides in the debate should show respect for each other and focus on the facts, the MPs said.
The committee also said the Government should look at the environmental impact of extending the ‘y-route’ branching northwards to Manchester and Leeds before a final decision on HS2 is made.