This is a walk across Stanmore Common to Aldenham Country Park using part of the London Loop long distance trail. You can park at the Stanmore Common car park off Warren Lane to start your walk. The trail then takes you across the park's woodland and heathland before passing the two artificially created ponds. You then head along the eastern side of the common to Aldenham Reservoir where you can enjoy a waterside stroll and grab some refreshments at the cafe. You can then return to the common on the same paths. It's just over a 2 mile walk from the common to Aldenham so about 4.5 miles in total.
There's lots of wildlife to look out for in this area. Keep your eyes peeled for muntjac deer, spotted flycatcher and bullfinch on your walk.
You can extend your walk by heading west along the London Loop to Harrow Weald Common and Oxhey Woods. The woods have an excellent 1km sculpture trail with various carved wooden pieces and a rhododendron trail to try.