It's in West Wickham in the borough of Bromley about 10 miles southeast of central London. Local development kickstarted in 1925 when the railway line to Hayes was electrified, and pretty much the entire suburb was in place by the time WW2 broke out. The longest residential roads spread across fields to the east of the station connecting to Pickhurst Lane, two of which manage to have no other junctions along their length. Longest is Wickham Chase, marked here in red, which at 1100m I believe to be the longest unbroken road in London. And running parallel is Langley Way, which at 940m I believe to be the second longest unbroken road in London. Both take at least ten minutes to walk from one end to the other.
Wickham Chase is a spacious suburban avenue lined by comfortably large, but not massive, houses. Some are detached and some look like they're chunky semi-detacheds but are actually joined together into longer chains. The architects plainly had a thing for halftimbered gables but generally did a good job of sprinkling the Chase with variety because at these prices nobody wants to look exactly like everyone else. These houses are all blessed with big front gardens, generally enough for three or four cars but two is more normal because most owners have kept some greenery out front. Long unbroken roads tend to be good places for parking cars, we have discovered.
It's the kind of street where builders stay for weeks, where scaffolders fix poles to help create loft extensions, and where vans bring carpet cleaners, dog groomers and lawn care specialists to do their work. I even turned up as the windowcleaner squeezed his sponge dry outside number 270, the last house in the street, because that's how long Wickham Chase is. Just when you think you've been walking long enough and the end must be near it veers left and lo, dozens and dozens more white-fronted houses line the gentle ascent ahead. This climb is also where Wickham Chase crosses the Greenwich Meridian, because it's obligatory to mention this on my blog whenever it happens.
You can't drive out of Wickham Chase except at each end, but there are footpaths in the middle cutting through to two parallel avenues and the local bus stop. Cycling is forbidden along these alleyways, although the maximum penalty is only £5 according to the ancient concrete sign so I dare say everyone risks it. What's intriguing looking back at maps from fifty years ago is that these show a road connection too, about 100m further along, up what now looks like an overgrown driveway alongside number 144. This section of the road has a lot of rear driveways, each overzealously added to Google Maps and OpenStreetMap as if somehow important, but one was once deemed worthy of inclusion on an Ordnance Survey map which must mean Wickham Chase wasn't always a junctionless road.
So I'd like to propose that Wickham Chase is London's longest unbroken residential road, at least as far as vehicles are concerned. But Elgin Road still retains the crown for the longest street not even pedestrians can escape from except at each end.
Various other roads may be debatably longer, depending on your willingness to accept sliproads, carparks, non-residential streets and country lanes, for details of which see Monday's comments.
After which the obvious question should be What's London's shortest street? I'm not going to stipulate 'shortest unbroken street' because the shortest obviously won't have any junctions. But I would like to stipulate that this road needs to have at least one front door, i.e. it's someone's address, otherwise any old mini-connector might count.
The identity of London's shortest street isn't something you can determine by scouring maps. It'd be much too short to show up unless you really zoomed in, and even then you wouldn't be able to tell if it was a proper street or not without taking a proper look. I am not willing to follow Streetview round the entirety of London just in case, so I suspect this is going to be a much more contentious title. So what I've done is take the easy way out by Googling "London's shortest street" to see what other people think it is.
This ridiculously brief thoroughfare is in Bankside between Mint Street Park and Borough tube station. It's also a proper street because it has buildings in it, including apartments and an actual pub. That pub is The Lord Clyde at number 27, a Southwark treasure rebuilt in 1913 and CAMRA-favoured. The ridiculously high house number is because this used to be Peter Street but that was split in 1927 into Clennam Street and Doyce Street, named after two characters in Little Dorrit. Alas Clennam Street was pedestrianised in 2010, mainly to give The Lord Clyde somewhere to stick its outdoor tables, and a fully pedestrianised street arguably doesn't count.
This stupendously brief street lies on the edge of Bloomsbury behind Holborn Library. It's a broad cul-de-sac off Northington Street that's almost square in shape, a stub so short that it ends at a brick wall after a dozen paces. It was obviously once much longer, in fact 30-buildings-worth, and stretched north as far as Doughty Mews. But relatively recently the vast majority of the street was replaced by a Catholic primary school (because Camden has to squeeze them somewhere), so now all that's left is a pub called The Dickens. And even that's long closed and has been transformed into flats, but one of those has a front door in the right place to be 1 Kirk Street so hurrah, this brief street counts. Or maybe it did when you could still park outside, but number 1's 'front garden' has grown over the last few months to include more obstructive planters so maybe it doesn't count after all.
Rob from RealCycling thinks cul-de-sacs don't count, you need a junction at each end, and reckons the next shortest street is Candover Street (42m) not far from the BT Tower. I reckon there must be a shorter street than that somewhere in Greater London but I can't be bothered to dig further, this whole 'shortest street' question is a complete can of worms and therefore not worth sweating over. What I can say is that you can get 55 Clennam Streets into one Wickham Chase, and that's the long and the short of it.