S2 Colne Valley Viaduct Korda Lake View 2 (Photo: HS2 website/ Grimshaw)

Earthworks have also progressed, with 58% completed, involving the movement of nearly 92 million cubic metres of material. Construction has commenced on 158 out of 227 viaducts and bridges, with 13 structures already built. Notably, the 2.1-mile Colne Valley Viaduct, the UK鈥檚 longest rail bridge, has had its deck completed, facilitating the railway鈥檚 passage over various lakes and waterways near London.

Despite these developments, HS2 Ltd鈥檚 new Chief Executive, Mark Wild, has acknowledged significant cost challenges facing the project. He has initiated a comprehensive review aimed at a 鈥渇undamental reset鈥� of the programme to provide renewed certainty regarding cost and schedule.

Wild stated, 鈥淗S2 represents a significant investment in Britain鈥檚 future and in the last month I鈥檝e been inspired by the hugely impressive feats of civil engineering taking shape right along the route. New railways provide better journeys and they boost economic growth by fuelling investment in communities and businesses.

鈥淭he prize is clear. However, the programme is in a very serious situation that requires a fundamental reset to enable it to be delivered to the lowest feasible cost. I am committed to delivering this reset over the coming year to ensure the railway can be brought into service safely and efficiently.鈥�

The project has encountered various setbacks, including cost overruns and bureaucratic delays. Estimates suggest that costs could escalate to between 拢67 billion and 拢83 billion in current prices. A definitive cost estimate is anticipated to be available well into 2025.