HS2’s only single-bore tunnel completed in west London as it prepares to vanish from sight

The only single-bore tunnel on the HS2 railway has been completed, although before long it will disappear beneath thousands of tonnes of earth as the cut-and-cover structure is buried from view.  The new tunnel is positioned between the twin-bore Northolt tunnel and the Colne Valley viaduct – Britain’s longest railway bridge, which was completed last year.
Inside Copthall tunnel August 2025 (c) HS2
The Copthall tunnel near West Ruislip in west London was going to be an open-air