Balfour Beatty has been shortlisted for a major £6 billion contract to construct the White Horse Reservoir in Oxfordshire, marking a significant step forward in the development of one of the UK’s largest proposed water infrastructure projects. The reservoir, led by Thames Water, has been in planning for two decades and aims to address regional water supply challenges.

Originally known as the South East Strategic Reservoir Option (Sesro) and sometimes referred to by its proximity to Abingdon, the project has been officially named the White Horse Reservoir, reflecting its location near the iconic prehistoric chalk carving on the surrounding hills. If completed, it would become the country’s second-largest reservoir after Kielder Water in Northumberland, surpassing Rutland Water in the East Midlands.

Balfour Beatty is partnering with the French construction firm Vinci, with whom it is also collaborating on other large-scale infrastructure projects, including parts of the HS2 high-speed rail network. Their joint bid will compete against two other international consortia: the WFH Joint Venture, comprising Italy’s Webuild, Spain’s FCC, and South Korea’s Hyundai Engineering; and a partnership of the French company Bouygues, London-based J Murphy & Sons, and Volker Fitzpatrick, a subsidiary of a Dutch parent company.

Despite the project’s progress, the White Horse Reservoir has generated significant local opposition. Critics argue the reservoir is not the optimal solution to water shortages in the region, citing Thames Water’s ongoing issues with high leakage rates and suggesting that upgrading existing infrastructure could yield comparable water savings. Additionally, concerns have been raised about the potential loss of water through evaporation from such a large open reservoir.

Financial questions also surround the project, as Thames Water has faced longstanding financial difficulties, including near insolvency and debates over potential renationalisation. Details concerning the reservoir’s funding have yet to be disclosed, further complicating assessments of its feasibility.

Even under the most optimistic timelines, the reservoir would not become operational before 2040, given the scale of engineering and environmental considerations involved. As the bidding process advances, the final selection will determine which consortium will undertake what could be a transformative piece of infrastructure for southern England’s water supply network.