Londonist travel news and features are brought to you in partnership with CommuterClub. Get better value on your daily commute.
Work is well underway on the extension of the Northern line, all the way down to Battersea. We went behind the scenes on the construction site to find out what's going on.
Find out why these tunnels are being built larger than any others on the Underground, and the answer to that all-important question; when will it open?