A 20-year-old campaign to bring the Northern Line to Streatham has been resurrected.

Plans to extend the Tube line by creating a second southern branch, going from Streatham to Kennington, have been dusted off by Lambeth Liberal Democrats and handed to London Mayor Boris Johnson.

The latest suggestions stem back to century-old plans for the original line.

The proposed branch would follow the A23 from Kennington to Streatham, stopping at Brixton.

The last campaign to see the extension become a reality was run 20 years ago by local transport campaigning group Streatham Against the Roads (Star) .

The Lib Dems have submitted the plans to Mr Johnson as part of the consultation on his London transport strategy It follows Labour parliamentary candidate Chuka Umunna's own Tube campaign - that hopes to extend the Bakerloo line to the area.

He argued, when launching the campaign last year, the Northern Line was already at maximum capacity and could not be expanded.

Both parties admit any extension is unfeasible until public finances improved significantly after the recession.

Chris Nicholson, Lib Dem parliamentary candidate, said: "Public transport to Streatham has to be improved but the central point is that rail usage to this part of London is currently beyond capacity.

"There needs to be additional capacity created ideally through a tube extension to Streatham, which would also help relieve the dangerous overcrowding on the existing southern part of the Northern Line."