CONTRACTORS building a new viaduct for HS2 today made history as they lowered into place its final deck segment to make it Britain’s new longest rail bridge.

The gently-curved 2.1 mile-long structure stretches across the Colne Valley near the M25 motorway and the village of Denham.

It will carry high speed trains running to and from the capital at speeds of up to 200mph.

Previously, the Tay Bridge, linking Fife and Dundee, held the record.

It is one of 500 bridge structures on the HS2 project, which also include footbridges, drainage culverts and 'green bridges' for wildlife.

Building work on the viaduct’s deck began in May 2022. Over the following 28 months, a team of engineers used a massive launching girder to lower into place the bridge’s 1,000 uniquely-shaped deck segments.

The pre-cast segments are made on-site at a purpose-built factory. Each of the segments is uniquely shaped to enable the structure to curve as it carries the high-speed line above land and water.

Once the main phase of construction ends, the factory and surrounding buildings will be removed and the whole area will be transformed into an area of chalk grassland and woodland.