Four and a half kilometres of water, west. You start above the lock at Camden — not in the market; the market is a separate problem for another day — and you walk the towpath until it stops being a towpath and becomes a set for a BBC costume drama. That's Little Venice.
The good bit is the middle. You pass the back of London Zoo, close enough to hear the birds; then you're through Regent's Park proper, where the canal feels like someone landscaped it for a painting. The moorings at Lisson Grove are the accidentally photogenic stretch — floating gardens, hand-painted hulls, a cat asleep on a tarp. Resist photographing any of it. Just walk.
Finish at the triangle in Little Venice, where three canals meet, and then either get the bus back or walk ten minutes up to Warwick Avenue. On a flat grey afternoon, this is the most reliable walk in London.
