Up to £5bn will be invested over the next six years on thousands of miles of water pipes, sewer networks, treatment works and other assets.

The programme of work will help to deliver net zero emissions water and waste water services by 2040 and build capacity in the network.

The successful companies are:

• Clancy
• Galliford Try Infrastructure Ltd (Morrison Construction)
• George Leslie Ltd
• RWGM joint venture
• Ross-shire Engineering
• WGM Engineering & BGEN joint venture
• Morrison Water Services

The initial work period spans the next six years with a six-year extension option thereafter under the Delivery Vehicle 2 (DV2) programe.

The range of work covers repair, refurbishment and replacement works, covering mechanical, electrical, engineering, civil engineering, construction and maintenance services.

Mark Dickson, Scottish Water’s Director of Capital Investment, said: “This represents a significant milestone in the delivery of our service and investment activity.

“The companies and joint ventures appointed to carry out this work on behalf of Scottish Water will play a vital role in ensuring customers have the most resilient network which brings them water and removes and treats waste water daily.

“The procurement itself has been a lengthy and rigorous process – the biggest we have ever undertaken. The team at Scottish Water is looking forward to working with our partners to progress our ambitious plans for the next decade and beyond.”

Galliford Try estimates the deal will be worth around £350m to the company.

Steve Slessor, Managing Director for Galliford Try’s Environment business, said: “The majority of our work in this sector is conducted within long-established collaborative relationships developed over many years, engendering a genuine sense of partnership so we are delighted to have been selected once again by Scottish Water on this important delivery vehicle for water and wastewater infrastructure.

“We look forward to working in partnership to deliver industry- leading innovation, efficiency and lower carbon initiatives while supporting a sustainable supply chain.”