The two ECI packages cover design and development work across a dozen wastewater treatment sites and come on top of £29m of similar AMP8 wins secured earlier this year.

A £20m tranche covers early-stage design at six plants: Chickenhall, Fullerton, Leeds, Newnham Valley, Paddock Wood and Sellindge.

Upgrades will lift capacity and boost compliance as Southern Water pushes ahead with its WINEP environmental commitments.

The second, worth £24.5m, covers six more sites at Dambridge, Felbridge, Staplehurst, Ticehurst, Tonbridge and Ulcombe.

Kier’s brief includes developing plans to improve ammonia, phosphorus and BOD removal while de-risking later construction stages through detailed constructability work.

Both deals run under NEC4 and aim to lock in programme certainty before the main build phases get underway.

Kier framework director Andy Beech said: “These awards represent another important step in our partnership with Southern Water at the start of AMP8.”

The latest wins reinforce Kier’s growing influence across AMP8 after recent successes with Yorkshire Water, Wessex Water, United Utilities, Anglian Water and Severn Trent.