Britain now has a new longest railway bridge as the HS2 Colne Valley Viaduct reached its full extent.

Contractors made history today as they lowered the final deck segment into place, surpassing the 3.3-kilometre Tay Bridge linking Fife and Dundee.

The 3.4-kilometre (2.1 mile) viaduct stretches across the Colne Valley near the M25 and Denham and will carry trains travelling at speeds of up to 200mph.

(Image: HS2)

(Image: HS2)

HS2 Ltd senior project manager Billy Ahluwalia said: “Lowering the Colne Valley viaduct’s final deck segment into place today marks the culmination of more than 10 years of planning, design and construction.

“I pay tribute to the dedicated team that has delivered a bridge that is both the longest on HS2 and has become the United Kingdom’s longest railway bridge – taking a record that had stood for nearly 140 years.

(Image: HS2)

“That is a historic achievement of which we can all be immensely proud.”

Building work on the viaduct’s deck began in May 2022. The project will now move into the next stage, installing railway systems, as it progresses towards being operational between 2029 and 2033.

(Image: HS2)

The factory used to make the segments on-site, and surrounding buildings, will be removed so that the area between the viaduct and the Chiltern Hills tunnel can be turned into chalk grassland and woodland.

(Image: HS2) (Image: HS2) (Image: HS2)