The North Downs offer the most in-vigorating walking within the M25 girdle. This well-signposted route is one of two Downlands Circular Walks inaugurated in June and awarded a kite mark for excellence by the London Walking Forum. Its highlight is one of England's most remarkable early medieval artworks.

By car from London, turn left off the A23 down Marlpit Lane, immediately before Coulsdon South Station. Take the second on the right, Downs Road, and after a few yards keep ahead where Downs Road forks right. You ignore a small car park and pass on to a second, larger one beside a disused restaurant.

Just behind this building a sign tells you: 'Downlands Circular Walk starts here'. Go through the gate into Devilsden Wood, a shady beech hanger that falls away steeply on your left. Soon a sign for Happy Valley reassures you that you are on the right route.

Coming out of the wood on to open downland, follow the pointer on the 'permissive path to Chaldon church'. (This means that it is not a right of way, but you are allowed to walk on it.) Keep to the right-hand edge of this field, rich in wildflowers - scabious, cowslips, oxeye daisies and more.

The path dips briefly into the wood, then re-emerges into the open, with the wood still on your right. After the next field, turn right at a signpost back into the wood, on a flinty uphill track. This emerges on to a broad path through an oat field, with fine views in all directions. At the end of the field, turn left on to the road and after a few yards fork right to reach the entrance to the church.

There was a church here in Saxon times and it is mentioned in the Domesday Book. The flint west wall was probably part of the original building, but the rest dates from the 12th to the 14th centuries, with the spire added in Victorian times.

The Norman font, the 17th-century pulpit and the memorials all repay examination, but nothing is as spectacular as the 12th-century mural on the west wall, the earliest known English wall painting. It is a spirited depiction of Judgement Day, showing the scramble to climb the ladder of salvation to Paradise, while below the damned struggle to escape the demons who drag them to torment.

Suitably uplifted, turn left as you leave the church and then fork right, passing to the right of the village sign. Turn right on the road for a few yards, then left down a path signposted to Piles Wood. This takes you back across the oat field, on a more southerly track, then follows the right-hand edge of Piles Wood to link with a wider path. Here turn left, following the sign to Happy Valley.

You pass some houses, a small paddock and a holly hedge on the right. After the last house, Broadwood, the path plunges back into the trees and past bramble bushes that will be producing masses of blackberries at any moment. At a junction go straight on, ignoring the stile on your left. The path goes quite steeply downhill and suddenly emerges from the trees at the bottom of the valley.

Turn left here (signpost: Farthing Down). If you feel like a drink, turn right at the second of two close-together signposts for a detour to the Fox (three-quarters of a mile each way), returning to this point when refreshed.

Keep walking along the valley floor and briefly enter a wood near some rustic picnic tables on the right, following a signpost to Farthing Downs. Bear left at the next signpost and go into the wood, rather than up the steep grassy slope. On the edge of the narrow uphill track you may spot wild orchids. At a broader path, turn left uphill and, emerging from the trees, sharp left to get back to the car park.

A leaflet about this walk, and also a longer seven-mile version, is available from Alex Baxter-Brown at the Downlands Countryside Management Project in West Ewell (081-541 7282).

Distance: 3 miles

Time: Under 2 hours, but add an hour for pub detour

Car Park: On Ditches Lane, Farthing Downs, east of Old

Coulsdon (see text for directions)

Train: Coulsdon South, then walk for a mile to the car park

Bus: 50 to Coulsdon South

(Photograph omitted)