Stretching for 3.4km, the viaduct near  Hillingdon was cast by concrete specialist Kilnbridge working in partnership with engineers from HS2’s main works contractor Align JV.

Weighing in at around 370 tonnes, the 6m tall reinforced concrete pier was cast on site using a specially-designed formwork. This was then removed after four days to reveal the final product.

Each pier is designed to support the full weight of the deck above and rests on a set of concrete piles going up to 55m into the ground.

This foundation work began earlier this year and will require the construction of 292 piles and 56 pile caps across the whole length of the viaduct.

The construction team have also now completed the first of four jetties across the lakes to get equipment into position to support the construction thereby taking construction vehicles off local roads. Where the viaduct crosses the lake, the piles will be bored directly into the lakebed, using a cofferdam to hold back the water while the pier is constructed.

Align’s project director, Daniel Altier, said: “I have no doubt that the viaduct will become one, if not the most striking element of HS2 phase 1 once complete.”

The main deck of the viaduct – which supports the railway line – will be built in 1000 separate unique segments at a temporary factory nearby before being assembled from north to south, starting next year.