Contractors Costain and Vinci have been awarded an £86m contract to build a water tunnel in Scotland.

The Shieldhall tunnel for Scottish Water in Glasgow will be the largest waste tunnel in Scotland.

It will be 4.7m in diameter and 3.1miles long. The firm said it was the “biggest upgrade of Glasgow’s waste water network in more than a century”.

The tunnel will run from Queens’ Park and the Craigton industrial estate in the city.

Work is due to start this month and complete in early 2018.