Their Royal Highnesses The Prince of Wales and Duchess of Cornwall ventured beneath the city of London to see a billion-pound electricity supply project that has future-proofed the city's electricity for decades.

Today The Prince of Wales and The Duchess of Cornwall officially opened the @nationalgriduk London Power Tunnels project, a 32km electricity superhighway below London's streets. pic.twitter.com/fHLbdhErwf

— Clarence House (@ClarenceHouse) February 7, 2018

During the visit, The Prince of Wales descended down 16 flights of stairs, to travel into the tunnels to see the work which has been done to create the electricity superhighway. pic.twitter.com/l65FFYGaeC

— Clarence House (@ClarenceHouse) February 7, 2018

The Prince of Wales was the first to see the project wearing a hard hat, high visibility jacket and heavy duty gloves, and descended 16 flights of stairs to see at a network of tunnels carrying huge cables under the capital's streets,

The project, to rewire the capital in order to meet electricity demand, began in 2011 and will be completed this year. More than 200km of cable has been installed in the network. pic.twitter.com/gtqfbf2mjV

— Clarence House (@ClarenceHouse) February 7, 2018

He walked along a small section of the 20 miles of concrete-lined passages, bored out during the seven-year project. With a tour given by National Grid's Chief Executive John Pettigrew, of some of the tunnels 105ft (32 metres) below the surface.

On the surface, The Duchess to learn about the National Grid's electricity superhighway scheme. She met with schoolchildren who were visiting the Grid's education centre, set up to encourage young people to learn more about STEM (Science, Technology, Engineering & Maths) subjects.

During the visit The Duchess of Cornwall met schoolchildren who have visited the @nationalgriduk education centre, set up to encourage young people to learn more about STEM (Science, Technology, Engineering & Maths) subjects. pic.twitter.com/s8NVNk71R9

— Clarence House (@ClarenceHouse) February 7, 2018

The Duchess of Cornwall talks to apprentices at the London Power Tunnels project. #STEM pic.twitter.com/uNFLm7EMRg

— Clarence House (@ClarenceHouse) February 7, 2018

Together Their Royal Highnesses met staff, stakeholders and local community members and then  launched the project, by both pressed a button as the song ‘I've Got The Power’ by Snap played from speakers. Their Royal Highnesses then inspected a plaque that commemorated the event.

And it's open! The Prince of Wales and The Duchess of Cornwall push the button to officially open the London Power Tunnels @nationalgriduk pic.twitter.com/571Emoug2G

— Clarence House (@ClarenceHouse) February 7, 2018

Their Royal Highnesses then had a chance to talk to staff and community members at a reception afterwards, as well as young apprentices. pic.twitter.com/y4uz7NM3El

— Clarence House (@ClarenceHouse) February 7, 2018

Women in Journalism Event:

In the evening HRH attended the women in Journalism event. You can read the report by Royal Correspondent for Daily Maily Rebecca English here