The National Trust has questioned the government’s refusal to tunnel the controversial HS2 route underneath the Chiltern Hills as protestors continue to fight their case.

Last week campaigners’ pleas to build HS2 under the Chiltern’s AONB were rejected in a final report published by the HS2 select committee.

National Trust chiefs have branded the decision “disappointing”; although encouraged recommendations that HS2 Ltd should engage more with communities affected by the high speed rail line.

London and south east director for the National Trust, Nicola Biggs said: “Areas of Outstanding Natural Beauty are designated to protect their importance to the nation.

“HS2 as the nation’s biggest infrastructure project for decades should have the best mitigation for its route through the AONB. This is why we have supported calls for a fully bored tunnel.”

However the trust has welcomed fresh negotiations with the government which offer better protection for places in its care across south Bucks.

This includes tree planting and screening around the HS2 Stoke Mandeville Maintenance Loop in the hope this will protect views on the edge of the AONB from Coombes Hill.

And it has pledged to continue to put pressure on HS2 to reduce the impact of construction traffic in West Wycombe and the visual impact of the rail line and maintenance depot at Claydon House.

Ms Biggs continued: “We believe that with good community engagement HS2 Ltd will be better able to deliver a railway that is sensitive to local needs rather than just creating negative impacts.

“The National Trust listened carefully to what local residents and experts told us which helped us put the best proposals to HS2 Ltd as to create the best solutions for all.”

In September it was announced that the rail tunnel would be extended through parts of south Bucks, leading to plans for a separate “green” tunnel – designed to reduce noise and help blend the line in to the landscape – to be scrapped.