Murphy Group says it has introduced “new thinking and innovation” on the 3km (1.8-mile) Crossrail tunnel under the River Thames from Plumstead to Woolwich.

The company fitted a fibre optic system embedded into the concrete rings supporting the tunnel structure, to provide detailed knowledge of how the structure behaves in use. The sensors monitor ground movement, the effect of loading caused by tidal changes, and the structure’s ongoing integrity.

Another claimed first was boring the tunnel (in the joint venture with Hochtief) using groundwater rather than potable water. The dewatering process is estimated to have saved two million litres of potable water per week, reduced carbon emissions by 23 tonnes, and saved £100,000.