The Victoria line was the newest whole line to be built (it was opened in 1968), but the Jubilee is newer, although it drives on the exact tracks Metropolitan line did in 1933, the Jubilee opened in 1979, and extended from central London eastwards to the Docklands and Stratford in 1999.
The London Underground did give the East London line to the London Overground to ease its traffic.
On the London Underground map, the Circle Line is coloured yellow.
Central Line
The Circle Line Unfortunately this answer is wrong! According to Transport for London the only tube line to connect all London Underground lines is the Jubilee Line.
You need to get the Northern Line to Leicester Square and then the Piccadilly Line to London Waterloo.
Hammersmith and City.
Jubilee Line.
It's on the BAKERLOO Line.
Hammersmith & City line
Black.
Green is the District Line
How many feet underground is the Circle Line in London, UK