In the only written reference I've found, Freddie, G W C Green in 'The Story of Wandsworth and Putney' (c. 1920) mentions an underground passage and hints at a tunnel to Fulham Palace! Which is of course complete fantasy. Isn't it?! It crossed my mind, Karl, when I started thinking about the tunnel (which I'm 99% sure exists), whether it could possibly be used, if found and opened up, as part of the much-discussed pedestrian underpass under the High Street, which would also link up the Thames Path. However, I fear that the Thames Water CSO project, and the development of the vaults by Boma Bridge (now TM) and Putney Pies had sadly put paid to the idea.
Philip John Evison ● 1701d