The project was to install a corrugated tunnel liner to upgrade and extend an existing underpass for the Sustrans coast to coast cycle network beneath the A1(M) at Birtley near Chester le Street.

The large-scale upgrade project was overseen, implemented and led by the Highways Agency and Interserve. The main area of the works consisted of the upgrading of the footpaths and coast to coast cycle route, incorporating the installation of an upgraded asphalt track with liner bridge supporting structure. Further to the hard-landscaping upgrade, the reshaping of the existing soft landscape had to be done in accordance to the new profile of the lining structure to ensure the project blended in to its new environment. Due to the severity of the upgrade, a full diversion to the cycle route was implemented and rerouted around the bridge