Tata-owned Agratas confirmed this morning that the contractor has signed a pre-construction agreement to deliver Building One, comprising 2.6m sq ft of built area.

Rival bidders are understood to have included Wates and ISG.

Sir Robert McAlpine will now start preparations for the mega-project, which will employ 2,100 workers at peak construction, many across Tier 3 and 4 of the supply chain.

Preparatory works have been underway at the site for several months already, with piling expected to commence in the coming weeks with 12,000 piles due to be installed.

Bristol earthworks specialist Kelston Sparkes has been on the site for several months. Its two-year ground and earthworks deal includes a huge piling-mat-installation of over 1km in length and 750m wide, requiring approximately 1 million tonnes of aggregate.

Model of the three big factory units for 40Gigawatt battery plant

Joe Hibbert, vice president for Capital Projects at Agratas, said: “The beginning of this partnership with Sir Robert McAlpine is another pivotal moment for our nationally significant project.

“The team brings an unrivalled commitment to technical excellence, client service, sustainability and exemplary project delivery, and most importantly, they live and breathe our shared vision of placing community at the heart of everything we do.”

Grant Findlay, executive managing director for Buildings at Sir Robert McAlpine, added: “Across our 155-year history, we have always been at the forefront of industrial change in the UK. This is why we are proud to be working with Agratas as its preferred delivery partner.”

Production at the new gigafactory is due to start in 2026. Two other buildings will also be built at the site in later phases.

Once all phases of construction are complete, the facility is set to be the biggest of its kind in the UK and by the early 2030s will contribute almost half of the projected battery manufacturing capacity required for the UK automotive sector.