The Lower Thames Crossing will be a new connection between the counties of Kent and Essex. Critical part of the new route will be a twin bore tunnel crossing under the River Thames east of Gravesend and Tilbury.

The crossing itself will cost £6.8 billion, but investment in local roads is also likely to be necessary to deal with the predicted increases in traffic once the crossing opens.

https://www.constructionnews.co.uk/civils/details-of-27bn-roads-spending-revealed-11-03-2020/