• Work to install electricity cables well underway with first section due to go live later this year
• £1billion project will help ensure London has the power it needs to maintain its status as a leading global city

After four years of digging beneath the bustling streets of London, tunneling has now been completed on National Grid's flagship London Power Tunnels project.

The final breakthrough occurred at Kensal Green and marks the end of an era for the project team who first began sinking the tunnel shafts in 2011.

It's been a truly epic undertaking that has seen engineers working around the clock to carve out a 32km network of tunnels using two giant sized TBMs (Tunnel Boring Machines) named Evelyn and Cleopatra.

Working at depths typically ranging from 20 to 60 metres underground engineers have had to negotiate the challenges of tunneling beneath the Thames and working around London's existing labyrinth of tunnels, sewers and underground bunkers.

David Luetchford, National Grid's Head of Cable Tunnels said: "This is a really exciting landmark and takes us one step closer to the completion of the project.

"It's amazing to think that over the last four years our tunneling teams have been digging around the clock, with many Londoners unaware of what's been happening beneath their feet."

Since tunneling began engineers have excavated large amounts of London Clay. This has been put to good use with much of it being used to remediate former National Grid gasworks across the capital, so the land can be freed up for exciting redevelopment opportunities.

Installation of the high voltage electricity cables which will transport energy supplies across London is already well underway and the first section due to go live this year.

The tunnels will plug London into new sources of energy which will help ensure future demand can be met. Currently accounting for 20 per cent of the country's energy use demand in the capital is growing at a rate of around 5 per cent a year.

Mr Luetchford said: "This project will create a new energy superhighway deep beneath the capital which will help ensure Londoners continue to have the energy they need at their fingertips.

"When we switch on London Power Tunnels it will play a vital role in maintaining the capital's status as a leading global city - it's very exciting to be a part of that story."

The project is due to be complete and fully operational in September 2017 a year ahead of schedule. For more information go to www.londonpowertunnels.co.uk

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About National Grid

National Grid is one of the largest investor-owned energy companies in the world and has been named Responsible Business of the Year 2014 by Business in the Community. We own and manage the grids that connect people to the energy they need, from whatever the source. In Britain and the north-eastern states of the US we run systems that deliver gas and electricity to millions of people, businesses and communities.

In Britain, we run the gas and electricity systems that our society is built on, delivering gas and electricity across the country. In the North Eastern US, we connect more than seven million gas and electric customers to vital energy sources, essential for our modern lifestyles.

National Grid in the UK:

• We own the high-voltage electricity transmission network in England and Wales, operating it across Great Britain
• We own and operate the high pressure gas transmission system in Britain
• Our gas distribution business delivers gas to 10.9 million homes and businesses
• We also own a number of related businesses including LNG importation, land remediation and metering
• National Grid manages the National Gas Emergency Service free phone line on behalf of the industry - 0800 111 999 (all calls are recorded and may be monitored).
• Our portfolio of other businesses is mainly concerned with infrastructure provision and related services where we can exploit our core skills and assets to create value. These businesses operate in areas such as Metering, Grain LNG Import, Interconnectors and Property. National Grid Carbon Ltd is a wholly owned subsidiary of National Grid. It undertakes Carbon Capture Storage related activities on behalf of National Grid.

National Grid in the US:

• National Grid delivers electricity to approximately 3.4 million customers in New England and upstate New York
• We own 3.8 gigawatts of contracted electricity generation, providing power to over one million LIPA customers
• We are the largest distributor of natural gas in north-eastern U.S., serving approximately 3.5 million customers in New York, Massachusetts and Rhode Island.

Find out more about the energy challenge and how National Grid is helping find solutions to some of the challenges we face at www.nationalgridconnecting.com