The Tata-owned business will part company with McAlpine at the end of this month and is preparing to install a new construction partner to take the vast battery manufacturing scheme through its next phase.

Agratas has not revealed who will replace McAlpine, but industry sources told the Enquirer that logistics and data centre specialist TSL will take over the job.

McAlpine originally joined the project as construction manager, although insiders said its role increasingly shifted towards project management as Agratas opted to deal directly with a growing number of package contractors.

Sources close to the scheme also said progress had been hampered by delays in securing key decisions from the Tata organisation in India.

The programme first slipped after completion of the piling phase when Agratas redesigned and scaled back the first of three planned production buildings to reflect changing battery manufacturing requirements.

At the time the client acknowledged the move would push first-phase completion from 2026 into 2027.

After a delayed start to steel erection, Severfield completed the frame for Building One earlier this year, allowing work to move into the cladding, roofing and internal fit-out stages.

But further disruption followed in March when M&E specialist TClarke walked away from the project during the design phase of its work amid what insiders described as mounting relationship problems with Agratas.

Fellow M&E contractor on the job NG Bailey subsequently expanded its role to absorb much of the outstanding package, while McAlpine was expected to oversee delivery of the fire suppression works.

An Agratas spokesperson said: “As the project has progressed, we have determined that a different construction delivery model is needed to support the next phase of our development.

“Following a review of the project’s requirements, we have decided to transition to a new construction partner. We thank our existing construction partner for their support to date.

“This change reflects the evolving needs of the project, positioning us to deliver the next phase with the capability and focus required to meet our objectives safely, efficiently and on schedule.”

A spokesperson for Sir Robert McAlpine said: “Having successfully completed the first phase of Agratas’s battery manufacturing facility in Somerset, following extensive discussions, we have mutually agreed to part ways.

“We are now working closely with Agratas to support a smooth and orderly transition to a new construction partner.

“We are immensely proud of the progress and achievements made to date, done so in true partnership with our supply chain partners and remain committed to supporting Agratas with the effective handover to the next phase.”