Plans to upgrade a tunnel under the Thames, which is used for electricity infrastructure between Kent and Essex, have been submitted. If approved, the existing Thames Cable Tunnel, which links Gravesend and Tilbury, will be improved and two new headhouse buildings added. Headhouses are buildings which are needed to connect the tunnel and act as access points for National Grid workers. The documents, which were sent to both local authorities, reveal the project comes to try and help the UK cut greenhouse gas emissions to as close to zero as possible by 2050. It comes after a public consultation…