London: the step-by-step guide Michael Leapman escapes to the Kent countryside

bromley is one of the greenest London Boroughs and among the most considerate in devising country walks for residents and visitors. The Farnborough Circular Walk is one, starting and ending in an unremarkable Kentish village but taking in fine open countryside, a variety of wild flowers and a small piece of history.

Where the High Street joins Church Road, walk up Tye Lane, an alley whose metalled surface ends by the Albert Stables, continuing as a path between hedges. The white flowers of Queen Anne's Lace are prolific, and beyond the left-hand hedge is a field of well-advanced barley.

The walk is signposted with yellow arrows but these are occasionally confusing: at the first arrowed post you need to follow the red route straight ahead. Keep on through green metal posts and fork left when you reach an open field, round the left edge of a wood and ahead at the next arrow, now walking on a chalky track across the field of barley. You may hear the drone of light aircraft taking off and landing at Biggin Hill nearby.

The path now goes into a wood and, after passing a seat on the right, turns left to a low boundary stone bearing the initials JL. Here turn right on to a path that leads to Shire Lane. Turn right on the lane for a few yards until the footpath continues on the left, crossing another cereal field towards a line of pylons. At the end of the field go sharp right on a stony path, slightly downhill.

Take a close look at the nettles along this path, with their unusual pale yellow flowers. On the right, through the hedge, the fields sport carpets of buttercups in a more dazzling yellow.

Turn right on to a surfaced lane, fringed with white may blossom. Soon you get your first distant view of Holwood House, on the hill ahead. It was built in 1827, replacing the former home of William Pitt the Younger, Prime Minister from 1783 to 1801. Pitt made controversial "improvements" to the grounds, destroying an important prehistoric earthwork.

The lane curves right and meets Shire Lane, which you cross again to climb some steps through a squeeze gate, turning left on a fenced path parallel to the road, giving a better view of the house. Follow this path round the edge of the field, through more squeeze gates, finally turning right on a hedged footpath that first dips and then climbs the hill.

Halfway up you cross the drive to the house (not open to visitors) and soon afterwards, on the left behind wooden palings, is the decayed stump of a giant oak tree. This was the Wilberforce Oak, where in 1788 the reformer William Wilberforce, after a discussion with Pitt, resolved to work to end the slave trade. The view to the south-west must be much as the two men would have seen it, except for the pylons. On the right of the path are a commemorative plaque and a stone seat, unhelpfully sited behind a fence and a locked gate.

Continue ahead on the wooded path and descend some steps to cross Westerham Road into the woods of Keston Common. After 25 yards turn right on a pebbled path parallel with the road. Keep on this path to cross a car park and go down some steps to the left of a signboard. Here is Caesar's Well, a brick structure encasing a spring - once thought to have medicinal qualities - that is the source of the Ravensbourne River.

Beyond it are the man-made Keston ponds, part of the old water supply to Holwood House. Today ducks enjoy them, and they contain small white water lilies. Keep to the right of the ponds and follow the arrows to a small green at the corner of Westerham Road and Fishponds Road. Keep ahead on Westerham Road for about 200 yards, until you see a green bridleway behind the gardens of the large houses on the left.

From the occasional glimpses of the gardens, with showy rhododendrons at their peak, you can tell they are well cared for, but the tall wooden fence stops you getting a proper look at most of them, unless you stoop to peer through knotholes. Towards the far end of the path, which is nearly a mile long, lower fences give better views.

Eventually you reach the A21 at Bromley Common, where you turn right and have to walk alongside the road for about 400 yards until you fork right into Farnborough High Street. After passing the farm shop turn right between numbers 34 and 38 into Pleasant View Place, with its quaint tiny cottages. When you reach the sports field keep ahead between the football and cricket pitches, then turn left down the path on which the walk began, passing the stables to return to Tye Lane.

Leaflets about this and other walks in the area can be obtained from Bromley Borough Council on 0181-464 3333

Distance: Four-and-a-half miles

Time: Two hours

By bus: R1, R11, 358, 402

Car parking: In High Street, Farnborough (south of Bromley on A21)