The section between Letchworth and Royston follows the Icknield Way, with the deviations of modern bypasses at Baldock and Royston. The £43 million Baldock bypass includes the Weston Hills Tunnel.
The route between Letchworth and Royston follows the Icknield Way, with the exception of modern bypasses in Baldock and Royston. The Baldock bypass, costing £43 million, incorporates the Weston Hills Tunnel.