Two giant tunnelling machines digging HS2’s longest tunnels have reached the Little Missenden ventilation shaft,

Named ‘Florence' and 'Cecilia’, the enormous 2,000-tonne pieces of equipment have spent two years excavating the twin tunnels between the M25 and South Heath in Buckinghamshire that will help improve connections between London, Birmingham and the North.

Bucks Free Press: Little Missenden vent shaft site with A413 in the background (HS2)Little Missenden vent shaft site with A413 in the background (HS2) (Image: HS2 Ltd)

The news means that the construction is now more than three-quarters of the way through its 10-mile drive under the Chilterns.

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Additionally, as well as digging and lining the tunnels, engineers have also completed the excavation of five shafts that will provide ventilation and emergency access near Chalfont St Peter, Chalfont St Giles, Amersham and Little Missenden with an intervention shaft at Chesham Road.

David Emms, HS2 Ltd’s Project Client, said: “HS2 will transform rail journeys between London the midlands and the north, and free up space on the existing network for more freight and local services.

Bucks Free Press: Aerial view of the Little Missenden vent shaft under construction Summer 2023 (HS2)Aerial view of the Little Missenden vent shaft under construction Summer 2023 (HS2) (Image: HS2)

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“We’re seeing great progress on the tunnel, which will take our trains deep under the Chiltern hills, safeguard the woodlands and wildlife habits above and significantly reduce disruption to communities.

“The huge progress that Florence and Cecilia have made would not have been possible without a huge team in support - manufacturing the tunnel segments, excavating the vent shafts and I’d like to thank everyone involved.”