The routes described here focus on the green spaces in and around London. For city walks I highly recommend London’s Hidden Walks by Stephen Millar.
Look up the name of a route on the map below and scroll down to find a description of the route.
The routes are colour-coded based on distance:
<10km = green, 10-15km = blue, 15-20km = purple, 20-25km = orange, >25km = red.