NCN21 runs down the A23/Brighton line corridor, mainly offroad on well-engineered cycleways. Despite passing through central Redhill and Horley and frequently close to the Brighton main line, it is a rewarding ride of unexpected landscapes.
There is a choice of east and west start points; at Gravelly Hill on NCN21 or via Chaldon on NCN20. The path from Gravelly Hill is on a splendid drover’s track take care descending, under the M25, past the impressive Godstone (Green)sand quarry and briefly R, L, R on roads through Brewer Street 1.8. After charming Pendell Farm 2.5 NCN21 turns R for an offroad loop beside M25 – a moment of incongruous proximity to the thundering motorway. Cycle Orbital chooses to ignore, and short cuts via Pendell and Merstham Roads.
NCN21 has teamed up with NCN20 when they rejoin 3.1 But you follow NCN21 signage from now on. L into Mercers Country Park 3.4 and an interesting off-road ride follows to Redhill 6.1. There follows a brief section alongside the A23, but then, despite hugging the Brighton mainline, NCN21 keeps up the interest and mainly bucolic atmosphere (on mostly excellent off-road engineered surfaces) until Horley town centre 11.9. Gatwick Airport is increasingly evident, but NCN21 keeps you away from the hubbub through Riverside Park right up to the terminal building. Take the staircase or lift that bring you into South Terminal just by Arrivals and close to the station entrance.