A new 2.2 km, 400 kV electricity tunnel beneath the Thames between Tilbury and Gravesend, replacing the existing river crossing as part of National Grid’s Grain–Tilbury uprating programme. Excavation is complete and further construction remains. The map uses the new Tilbury shaft; a fully verified route is still outstanding.[1][2][3]
Tunnel boring machine Caroline broke through at Gravesend on 27 September 2026 after completing the 2.2 km Thames drive, 49 days ahead of schedule. Excavation is complete; the electricity connection remains under construction.
National Grid’s tunnel boring machine completed the 2.2 km drive beneath the Thames between Tilbury and Gravesend on 27 September, 49 days ahead of schedule. The breakthrough completes the excavation phase; further construction and cable installation are needed before the new electricity connection enters service.