The National Grid‘s London Power Tunnels (LPT) project has marked the end of its ambitious tunnelling phase.

The final tunnel boring machine (TBM), known as ‘Grace,’ emerged triumphantly at the Eltham substation in Greenwich last Saturday, concluding its 11-kilometre journey from the New Cross substation in Southwark.

This milestone signifies the completion of 32.5 kilometres of underground tunnels, an undertaking that has seen the excavation of 900,000 tonnes of earth, equivalent in volume to half of Wembley Stadium.

With the underground routes now established, the installation of 200 kilometres of high-voltage cables has commenced, connecting substations at Wimbledon and Crayford.

This network of cables, if stretched out, would span the distance from London to Cardiff.

Minister for Nuclear and Networks, Andrew Bowie, said: “This is part of National Grid’s wider commitment to rewire and modernise London’s electricity network, significantly increasing London’s capacity and energy security for years to come.”

Alice Delahunty, President of National Grid Electricity Transmission, said: “This complex engineering endeavour is now really taking shape, with completion of tunnelling now physically linking our sites across South London for the first time and meaning we can move on to the next chapter to progress our vital cabling work.”