2011-05-10 51 -0
In the exact middle of an M4 motorway bridge, in the exact middle of a freight-only railway, near Brentford/Hanwell.
MattLondon went -- as close as was legal.
Cycle along the Grand Union Canal (Brentford Branch), walk over the lock to "Osterly Lock" (according to the OS map).
I don't drive, so I can't use the M4; the railway has no passenger trains.
Osterley Lock looked overgrown, and there was nowhere to leave my bike. I continued along the canal to Trumpers Way, locked my bike to a fence and crossed the railway via the footpath. It was easy to follow the little-used path near the edge of the railway towards the motorway.
I could get to within 50m of the point, but no closer. Google Maps may be inaccurate, it's possible the point wasn't actually on the motorway, but in the private golf course on the other side.