Yep, you read that right!
My work colleague is a bit shattered after walking from Boston Manor to Hatton Cross yesterday. Him & his girlfriend have spent the last few weekends walking the entire Piccadilly Line from Cockfosters.
However, research and a BAA contact have advised him it's impossible to walk from Hatton Cross to T1,2,3 then onwards to T5 (T4 to Hatton Cross is feasible). Even with the Tunnel Road is this the case? I'm sure BA FT'ers have the definitive answer
Be a bit of an anti-climax if he has to miss out the last few stops - is this the case that there is no walking option?
(If the question is why, It's a nice way to see London , lots of pubs en-route, and apparently there is a useful app that points interesting things out along the way!)