An extension of the Metropolitan line is to go ahead after London Underground confirmed a funding plan for the new line.
Construction of the extension is now set to begin next year, opening in 2020.
London Underground plans to extend the Metropolitan line from Croxley to Watford Junction, where it will connect to the West Coast Main Line.
The project includes two new stations, at Cassiobridge and Watford Vicarage Road, and a viaduct.
Work can now begin as planned after a funding packgage was agreed between the Department for Transport (DfT), Hertfordshire County Council and Transport for London (TfL).
Once the extension opens, Watford Metropolitan station will close to the public but retained as sidings.
Nick Brown, managing director of London Underground, said: “For 100 years, the Tube has been enabling growth in ‘Metro-land’ and this new part of the Underground network will support further rapid development in the area.
“By 2020 we will have built a 400m viaduct, two completely new stations and numerous new and reconstructed bridges along the route, transforming transport links in Watford.
“With the funding package complete we’re now turning all our attention to appointing contractors, finalising designs and beginning construction in 2016.”
