Costain Group PLC

13 October 2025

Costain Secures £1bn Long-Term Programme With Sellafield

Costain Group PLC ("Costain") today announces that it has been selected by Sellafield Ltd ("Sellafield") as its Utilities Delivery Partner, a major part of Sellafield's Infrastructure Delivery Partnership ("IDP"). As Utilities Delivery Partner, Costain will refurbish and replace a variety of on-site and off-site utility distribution systems and services to enable Sellafield's decommissioning programme. The contract is expected to be worth up to £1bn to Costain and consists of an initial term of nine years with an option to extend by a further six years, either in a single extension or multiple smaller extensions. The total value of Sellafield's IDP is worth up to £2.9bn.

Alex Vaughan, chief executive officer of Costain, commented: "This new contract award with Sellafield, with whom we have been working with since 2005, is testament to our strategy of developing long-term relationships with tier 1 customers, building strong and collaborative partnerships, broadening our service offering, and maintaining consistency and continuity of workflows.

"This long-term award follows previous contract wins in the civil nuclear energy market this year with Sizewell C and Urenco and further demonstrates our integral position in this market. The Government is clear that the safe and responsible decommissioning of the UK's nuclear legacy is a critical part of creating a sustainable future and delivering local and national economic prosperity. As one of Sellafield's trusted partners we will deliver safe, high-quality utilities upgrades in a complex working environment."

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Costain improves people's lives by creating connected, sustainable infrastructure that enables people and the planet to thrive. Through the delivery of predictable, best-in-class solutions across the transport, water, energy and defence markets, we are creating a sustainable future and securing a more prosperous, resilient and decarbonised UK.

By bringing together our unique mix of construction, consultancy, engineering and digital services, we work strategically with our customers and suppliers to meet critical national needs​. Together, our people transform the performance of the infrastructure that connects, protects and powers people's lives.