Our first Colne walk (before lockdown) traced the river from its source at the Water End swallow holes near Potters Bar to London Colney, where we re-join it this time. A detour to Colney Street will take us to the River Ver for our morning tea stop, after which we continue downstream past stepping-stones to the confluence of the two rivers. We leave the Colne where it passes under the M1 (eventually to join the Thames at Staines) and cut back across country with a lunch stop by the village pond at Letchmore Heath. Please bring your own food as table reservations are now required at the refurbished gastropub. Distance: 18.5 miles (or a little more if we have to avoid muddy/flooded paths)