1912-1977

The first two maps were derived from Ordnance Survery maps of Greater London, which you can see for yourself here on the National Library of Scotland's Website:
OS map 1947 OS map 1957

1977-2002

The boundaries between 1977-2002 were far harder to determine.
Historical OS maps are only available online for dates prior to around 1960, as far as I am aware.
Therefore we resorted to using the Local Government Boundary report from 1977, which detailed the delimitation of the future boundaries (at the end of the document), and a map from the 2002 LGBCE draft proposal which showed a representaion of the boundaries as they were.

2002-Present

Present day boundaries were taken directly from the Open Data Camden Website and as such these boundaries are probably the most accurate of the bunch, being created by an official body.