Tunnel Replacement 

The existing Thames Cable Tunnel between Tilbury, Thurrock, and Gravesend, Gravesham is over 60 years old and is coming to the end of its useful life hence the need for its replacement.

The tunnel will be 2.2 kilometres in length and will run beneath the Thames between Tilbury and Gravesend. This has received planning permission, along with the headhouses and overhead line alterations, from both Gravesham Borough Council and Thurrock Council.

Headhouses and cable sealing ends

Two headhouses, and sealing end compounds, will be required as part of the development, at either end of the tunnel at Gravesend and Tilbury. This infrastructure is required to connect the existing overhead line route to the new cable in the tunnel, and to the rest of the electricity network.

It will also be necessary that we later deliver and install a new pylon at both the Gravesend and Tilbury headhouse sites, and remove three existing pylons at Tilbury. This is planned to take place from 2027/28.

Current project status

Tilbury

Following on from the approval of the proposals, we have spent the last couple of months undertaking site set up works, with the installation of site offices and ground preparation.

In October, we marked a major milestone with the delivery and installation of the Vertical Shaft Sinking Machine (VSM). This equipment is a cutting-edge technology that will enable safe, efficient, and environmentally responsible shaft construction beneath the River Thames.

Following an initiative with children at local schools, the VSM has been named in honour of Verena Holmes and the TBM named in honour Dame Caroline Haslett.

In the coming months, we will take delivery of the Tunnel Boring Machine (TBM), which will construct the new tunnel under the Thames.

Take a look at our activity on-site at Tilbury from the last month

Gravesend

With the site set up undertaken, enabling work is underway on the Gravesend side of the River, in preparation for the VSM to be transferred over from Tilbury in early 2026. 

The cycle path surrounding the site will be shortly closed to ensure safety during the tunnel construction works. The full diversion route and details of the closure will be available shortly.