HS2 Ltd has started construction of an innovative green tunnel designed to blend the railway into the landscape.

       The one-and-a-half-mile-long structure in Chipping Warden, Northamptonshire, is being built on the surface of the ground to speed up the process.

       More than 5,000 concrete segments made in a factory in Derbyshire will be assembled on site, before being covered by earth, trees, shrubs and hedgerows to fit in with the surrounding countryside.

       Progress at the site (HS2 Ltd/PA)

       The overall project has faced fierce criticism about the impact it will have on the route of the line.

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       The green tunnel will be an m-shaped double arch with separate halves for northbound and southbound trains.

       Both halves will be the height of two double-decker buses.

       The tunnel is the first of its kind in the UK.

       Construction is expected to last three years.

       A visualisation of a green tunnel (HS2 Ltd/PA)

       A total of five green tunnels will be part of Phase One of the high-speed railway between London and Birmingham.

       HS2 Ltd’s project client Rohan Perin said: “The Chipping Warden green tunnel is a great example of what we’re doing to reduce disruption for people living close to the railway – and it’s fantastic to see the first arches in position.

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       “Our trains will be powered by zero carbon electricity but it’s also important to reduce the amount of carbon embedded in construction.

       “The off-site manufacturing techniques being used will help cut the overall amount of carbon-intensive concrete and steel in the tunnel and make the whole process faster, more efficient and therefore less disruptive for the community.”