Exit Hanwell railway station and follow the road in front as it bends to the left. At the end turn left and head towards the viaduct. Just before it, cross the road and join a tarmac path to the left of a small, enclosed park. A few paces further on take the paved path on the left and continue as it becomes a track (signposted to Greenford) running beside the Wharncliffe Viaduct. Isambard Kingdom Brunel designed the viaduct in 1837 and it was used by the Great Western Railway to carry trains from London to Bristol.

Go up the steps to your left, following the fingerpost signed 'Brent River Park Walk'. At the end of the meadows follow the path through the trees as it runs alongside the river. Continue across the grass towards St Mary's Church and follow the path next to the church, which slopes down. The area ahead is where the colonies of bats often feed. Many of these warm-blooded mammals hang from the nooks and crannies of Wharncliffe Viaduct, coming out at dusk to feed on insects along the river. You won’t see them in winter though, as this is when they hibernate, due to lack of food supplies.

Cross the tubular iron bridge, take the right-hand path and keep going to reach the golf course. Go immediately right over the lawn, pass the bench, turn right then left over the footbridge, emerging on to a golf course (beware!). Turn left and veer right at the ditch, go left down the slope to cross the ditch by the very narrow footbridge. Keep ahead with the river to your left.

Keep going straight ahead at the next bridge to join a red-gravel path. Fork left. Now continue on the grass path past a wooden bridge to your left and then go to the right of an area of reed beds following the meander of the river. The reed beds here provide not only nesting sites for reed warblers but also feeding areas for migrating birds, especially in autumn. Continue ahead past a weir. On arrival at the brown wooden fence go right up the steps and turn left along the red-gravel path, which runs alongside Bittern’s Field. Follow the path as it swings left and descends becoming grass again. At the end cross the busy Ruislip Road, bear right and go left through the gap in the rail to pick up the footpath once again.

After two weirs, the second of which is enclosed by railings, you will see Perivale Golf Course on the left. Continue on this path as it runs parallel to the road very briefly and merges with the pavement before veering to the left under the railway bridge. Go past a metal footbridge then go up some wooden steps. Pass to the left of Gurnell Sports Centre and turn left to pass a wooden marker post and head along the narrow, gently descending track, following the river along the edge of the sports field. Swing right and go up the incline.

Head left to join the main road and turn right along it. Cross over the zebra crossing, bear right and, just after the bench, veer left along the grass path and then left along the asphalt path. At a crossing of paths, keep ahead along a fenced path that slices through Ealing Golf Course. At the end turn left to cross a wooden bridge. Ahead is the white-timbered steeple of the 12th-century St Mary the Virgin Church in Perivale, whose churchyard is a haven for wildlife and features the rare black poplar tree. The church is now an arts centre and plays and concerts are performed here during summer weekends.

At the lychgate turn left and then right into Old Church Lane, passing the Myllet Arms pub. At the end cross the footbridge over the busy Western Avenue (pausing to admire the famous art deco Hoover building and the landmark arch of Wembley Stadium). Go left along Horsenden Lane South to reach Perivale railway station.