The A217 seems to have two distinct purposes: a minor urban A-road in south London and an important through route out of Greater London. As such the road is surprisingly long: it is one of few roads that genuinely connect central London with open country.
Section 1: Hookwood, Gatwick – Mitcham
The A217 starts a long way out of London, near the end of the M23 spur at Gatwick Airport at the junction with the A23. The first stretch, although undeveloped, is a useful bypass of the A23 through Horley and Salfords, as it follows the course of the River Mole. After about four miles we cross the river, as it turns westward towards the gap in the North Downs at Dorking on its way to the Thames at Molesey. The A217 meets the A2044, which connects with the A23 again, and enters Reigate. We now enter the one way system in Reigate, crossing the A25 in the process (until the 1970s the A217 went through the Reigate Tunnel, which is now closed to traffic), followed by the level crossing over the Redhill–Guildford–Reading line and then the steep hill up onto the Downs. All of this can make for slow progress, and it is with relief that we reach the top of the hill (especially on a bike!) and meet the M25. Unless the M23 is very congested, it is almost always quicker (unless you are on a bike!) to use the M23 and M25 from Gatwick to this point, but as there are no intermediate junctions (except the M23/M25 stack) the A217 and A23 necessarily serve all intermediate destinations.
North of the M25, the A217 is much superior to the A23, being dual (and primary) across the Downs and most of the way into Sutton, albeit now largely limited to 40 mph and punctuated by roundabouts – the one at Tadworth being signalised. The stretch between the M25 and the Banstead Crossroads was reduced from 70 mph to 40 mph after speed complaints from Lower Kingswood residents around the late 1990s. Average speed cameras have been in place to enforce this since Autumn 2017.
Reigate Avenue Railway Bridge, Sutton
At Burgh Heath the A240 turns off for Kingston – a useful route to the A3 and recently added to the primary network – but we press on towards Banstead, and after the traffic lights at Nork (A2022) a final fling at 60 mph across the Banstead Downs before we hit the Greater London boundary, and a roundabout. The original route (now the B2230) goes straight on here through Sutton, but we take a more westerly route through Cheam (of Tony Hancock fame). An excellently preserved pre-Warboys signpost, complete with separate triangle, still serves to warn southbound traffic of one of the "Cross Roads" on this stretch. At the Rose Hill roundabout, we meet the original route (B2230), but lose primary status to the A297 St Helier Avenue, which leads to the A24 at Morden.
The A217 now passes through the St Helier estate, one of the largest of the estates built by the London County Council in the 1930s (whilst creating much-needed jobs, it did spell the end of the local lavender and herb industry which had been based in the area). In deference to the proximity of Merton Abbey, the street names are named after ecclesiastical establishments, and are arranged alphabetically, the A217 passes between the "M"s on the left, and the "N"s, "P"s and "R"s on the right.
We now cross the River Wandle, and the course of the early 19th-century Surrey Iron Railway, built to ensure communication between London and the South Coast should Napoleon blockade the Channel – but only built as far as Merstham. The railway never prospered during the heyday of the railways – it ran across the main radial flows, but it survived and is now part of Croydon's tram network.
Section 2: Mitcham – Wandsworth Bridge
The A217 now negotiates two gyratories round Mitcham's Lower Green and Upper Green (where it crosses the A236), before heading for Tooting – the A216 to Streatham branching off to the right at a signalised roundabout. After Tooting railway station, an abrupt turn to the left at Amen Corner takes us to Tooting Broadway and the A24, which has shadowed us a little to the west almost since the M25.
Heading northwest now, along Garratt Lane and close to the River Wandle. The river lies sandwiched between the A217 and A218; the area between them is mainly industrial, whilst either side is residential. Garratt Lane debouches into the Wandsworth One Way system next to the Arndale Centre, but doesn't end here. It did once but the new relief road built to connect with Wandsworth Bridge is part of the A217. To the right is the impressive A214 Trinity Road dual carriageway (which peters out just out of view), whilst straight on is the A3205 York Road, but we go left over Wandsworth Bridge.
The bridge was built in 1940, replacing the original 1873 structure, and was originally numbered as the A3208. Once across the bridge, the road continues to meet the Kings Road (A308) at Walham Green in Fulham.