United Utilities seeks a design partner worth up to £600 million for its £3.7 billion Windermere clean-up

The water company issued the formal tender after an online launch event for suppliers on Oct. 29, WaterBriefing reported. Clarification questions are due by 2 p.m. on Nov. 17 and bids by 2 p.m. on Nov. 30. Construction Enquirer reported that United Utilities expects to name the winner on April 1, 2027, and have it start work on April 15. United Utilities will hire a single partner, which can be a consultant or a consortium, according to The Tunnelling Journal. The notice puts the value at £720 million with VAT.

The winner will carry the scheme through outline design, ground and site investigations, environmental impact assessments, land referencing, planning applications and bringing contractors in early. The partner also writes the application for a Development Consent Order: United Utilities wants the main works, from the tunnel and pressure mains to pumping stations and treatment plants, to go through the regime for Nationally Significant Infrastructure Projects, which needs Section 35 approval from Defra.

The development phase starts in April 2027 and lasts four years. After that, United Utilities can extend the deal in steps for up to nine more years: as system integrator, worth about £100 million, or as integrator and detailed designer, worth about £500 million. The two roles are alternatives, and the company says it may need no delivery-phase support at all. It has not picked a construction model. Options include backing a prime contractor or forming an enterprise that puts client, designers and contractors under shared incentives.

Jacobs and Mott MacDonald, which ran the feasibility study, whittled more than 70 ideas down to two, with about 14 km and 19 km of tunnel. The wider plan also calls for up to 138 km of new sewers, roughly 35 km of works to catch road runoff and sustainable drainage across 37 hectares. United Utilities expects building to take about seven years after the design is done and planners and regulators sign off.