** Updated Sun 08Mar2026 following final test. Start point and distance have changed. **

A circular walk of 9.5 miles in south-west Hertfordshire, a mix of rural and metropolitan countryside, delicately decorated with a thumping great motorway blasted through the rolling hills.

The route explores quiet suburbia, a glimpse of the Abbey Flyer railway line, field walking, lunch at an urban churchyard, the River Ver,, Frogmore Lakes, a sewage farm, the confluence of the Rivers Ver and Colne, and – the lo-light of the walk – the concrete insanity of M25 J21. The route uses a footpath bridge which transects the junction, a path Herts GOC last walked in Jul2012. It is a very giddying and discombobulating experience.

The route is exposed. Wear appropriate warm clothing.

Wear sturdy boots. Expect surface mud and some surface flooding.

Bring packed lunch, water and something to sit on.

Optional pub stop at the end of the walk.

The start point is close to a railway station, but the trains are infrequent, so the route might not be easily accessible by public transport.