A milestone for the Northern Line Extension was reached today as a huge tunnel boring machine broke through to Lambeth this week.

The machinery, named Amy, reaching its final destination at Kennington means the two 3.2km tunnels from Battersea Power Station, through Nine Elms, are now built.

Helen and sister tunnelling machine Amy have been working to create the north and southbound tunnels which will extend the Charing Cross branch of the Northern Line.

Targeted for completion in 2020, Transport for London (TfL) says it is the first major extension to a Tube line since the Jubilee Line in the 1990s.

It is said the extension will add new capacity to the capital’s transport network and bring Battersea to within 15 minutes of the City and West End.

It will also add to the regeneration of Vauxhall, Nine Elms and Battersea, with TfL claiming that there will be around 25,000 new jobs and more than 20,000 new homes as a result.

In addition, it is said it will boost the UK economy and support around 1,000 jobs, including 50 apprenticeships.

Speaking yesterday, Wandsworth Council leader Ravi Govindia said: “Today’s event is a real milestone in London’s first new Tube line extension for almost 20 years.

“This is an extremely important project, not just for the borough but the whole Capital, and Wandsworth has put in a lot of time and effort to shape the unique funding package that has taken us to where we are today.

“Working with the private sector we are now seeing our hard work come to fruition and the tunnelling machine breaking ground is a tangible reminder that the Tube extension will soon be a reality, transforming the fortunes of north Battersea and making the Nine Elms regeneration programme one of the greatest sources of new jobs and homes in the country.”

A conveyor system was used to transport more than 300,000 tonnes of excavated earth to barges on the River Thames, where it was later taken to Goshems Farm in East Tilbury, Essex.

The cutter head of both machines will now be lifted by crane out of the shafts at Kennington, and the rest of the machines will travel back to Battersea and be lifted, in parts, of the ground.

Rob Tincknell, chief executive of Battersea Power Station Development Company, said: “This is a really significant milestone in the regeneration of both Battersea Power Station and Nine Elms and reconfirms certainty about the two new stations.

“That such a vast extension to the London Underground network is being funded through the regeneration taking place throughout Nine Elms is a credit to all those involved in nurturing this project throughout the years and a powerful example of how new transport infrastructure can be delivered by the public and private sector working successfully together.”