Tilbury – October 11, 2026 -- National Grid's tunnel boring machine (TBM) Caroline completed a 2.2km drive beneath the River Thames 49 days ahead of the original programme, ending the tunnelling phase of the Grain to Tilbury project, part of The Great Grid Upgrade.

The breakthrough came on Sunday 27 September. Caroline excavated a new high-voltage electricity cable tunnel between Tilbury in Essex and Gravesend in Kent.