Highways England has started searching for contractors for the proposed Stonehenge tunnel project, which is intended to improve the A303 between Amesbury and Berwick Down in Somerset, UK.

The procurement process for the scheme is expected to involve an investment of around £1.7bn. The project is expected to last for 18 months.

The contract notice has been published in the Official Journal of the European Union (OJEU). The agreement covers the £1.25bn main works contract for the construction of the tunnel’s civil, mechanical, structural, electrical and technology components.

Contracts to facilitate the project’s preliminary works will be announced separately.

The project includes the construction of a 3.3km tunnel beneath the Stonehenge World Heritage Site, closely follows the existing A303 route but will be 50m further away from the monument.

The project also includes building a new bypass to the north of the village of Winterbourne Stoke, as well as junctions with the A345 and A360 either side of the World Heritage Site.

It is intended that the new scheme will ease congestion, support economic growth and enhance the setting of the historic landmark. Sorry, there are no polls available at the moment.

Highways England project director Derek Parody said: “We expect this scheme to be of interest to some of the world’s best construction companies, who want to be part of delivering this transformational project, a scheme which will not only unlock congestion along this vital A303 route, conserve and enhance the outstanding universal value of the World Heritage Site but also benefit the local and regional economy by providing skills and job opportunities for businesses large and small.

“This in no way pre-empts the outcome of the ongoing development consent order examination. While this continues to progress, we need to begin the procurement to put us in a position to be able to start construction on schedule in 2021, providing consent is given.”

In February, Highways England unveiled a consultation seeking public’s feedback to build a tunnel as part of the £1.6bn upgrade of the A303, which passes through Stonehenge.