I know I said that last time but there have been 'developments' and it turns out there was one more postcode district to go.
In my last post I expressed a nagging doubt that IG10, KT7, KT10, KT21, RM19, SL0, SL3, TW16 or WD19 might marginally overlap the boundary of Greater London, despite seemingly having no postal addresses in the capital. And hey presto, Ollie from UCL got in touch to say he'd checked the official Ordnance Survey database and there was one more address to consider. It wasn't a proper building, more a cafe in a layby, but it did have a postcode and it did get food safety inspections from Hounslow council so according to my rules it definitely counted. So I've made one last peripheral postcode trip to tick off TW16, now officially the last of the 244 districts I needed to visit, and I even celebrated with a drink.
TW16 is the postcode district for Sunbury, a town in former-Middlesex-now-Surrey a couple of miles upstream of Hampton Court. It's home to Kempton Park racecourse, the start of the M3 motorway and the end of a fair few stockbroker commutes. It's rather pleasant close to the Thames but gets more ordinary the further away you go. And it contains one rogue overlapping address because the Greater London boundary aligns with one watercourse and the TW16 boundary aligns with another, 200m apart.
The overlap occurs along the A316, an elevated dual carriageway which brutally divides the local community before swooshing down onto the floodplain and becoming a motorway. Our target is at one end of a layby on the Londonbound carriageway so is best approached from the general direction of Sunbury town centre, although there is a miserable passageway underneath the viaduct should you stop in the scrappier layby on the other side of the road. Laybys are obviously optimised for arrival by vehicle but this one thankfully has a connecting pavement and an implausibly close bus stop, the 290 having a remote drop-off just past Costco, eastbound only.
The layby offers motorway drivers their first chance for a welcome break since Fleet but isn't well signposted, indeed the banner advertising the cafe had come loose from one of its moorings and was lying uselessly face down on the grass. It's also nowhere you can buy petrol, travel chargers and M&S sandwiches, it's just a tree-lined turnoff with a scrappy verge and inadequate bins. You can tell the southern end of the layby's in Surrey because the 'please take your litter home with you' message comes is brought to you by Spelthorne council. But two-thirds of the way along is a small bridge over a smaller stream, the Felthamhill Brook, and that's where Surrey stops and London begins. If only the cafe had been at the southern end of the layby I wouldn't have had to come here.
When I say cafe what I mean is a shipping container painted blue. It's a very nice shade of blue with bright pink shutters so quite attractive as metal boxes go, but a box all the same. Hints that it's a cafe include a 'Cafe Open' sign plonked by the roadway, an overflowing bin outside and a big banner on the roof, except the banner faces the dual carriageway so by the time any drivers spot it they'll have overshot the entrance and unable to drop in for a fry-up. The name of the cafe is Browns Breakfast Bar, or perhaps the 3B's, or perhaps the 3B'S Browns Breakfast Bar, it hard to be certain. And if it's open (6am-2pm weekdays only) anyone can walk up a couple of brick steps, push through the dangling strips of translucent plastic and head inside.
It's amazing how much cafe you can cram into a shipping container if you try. To the left is the preparation area and frying section, straight ahead a wallful of menu options and to the right sufficient tables to service a decent-sized road crew. I entered just as a bullet-headed group of workmen were about to have their breakfasts delivered so got the added bonus of waiting while Rachel flipped the last rashers of bacon, pooled the beans and buttered the doorstops. Her culinary juggling was seamless, the smell was divine and I totally respected her decision to focus on delivering all four plates at optimal temperature before asking what I wanted.
The 3B's has an impressively broad menu, so long as what you want is some combination of breakfast, bread and burgers. You know where you are with seven set breakfasts, or ham, egg and chips, or jacket potato with cheese, or corned beef roll, or chicken burger with chips and beans or peas or salad. Splash on your choice of Sarsons, Heinz or HP from the bottles on the table and why would anyone queue for a smaller, fancier, more expensive brunch in the centre of town, other than to protect their arteries? I could have wimped out with a KitKat or a generic cherry bakewell but instead I plumped for a takeaway tea, rather than sit with the football-shirted, and rejoiced when Rachel took the teabag out before serving. You don't get that kind of service in Starbucks, let alone for a quid.
As I sipped my celebratory brew I smiled because I had now visited every postcode district in Greater London, or at least all of them with an address. I also smiled because the tea was good.
I wasn't smiling quite so much as I followed the pavement further into Greater London, descending off the viaduct to walk beside its concrete pillars through a heavily fortified waterworks. But it only took a minute to reach the austere trench that is the Staines Reservoirs Aqueduct, the invisible line where TW16 morphs into TW13, and that really was job done.
I knew I'd left TW16 because I'd reached the occasionally-unlocked access gate to the amazingKempton Steam Museum and the bijou Hampton & Kempton Waterworks Railway, and both their postcodes are TW13 6XH. I also knew I'd left TW16 because Ollie's database had introduced me to the concept of "addressable locations".
The Ordnance Survey keep a record of everything that might need to be located, not just houses and buildings but also bits of infrastructure like drainage ponds, silos and electricity substations. Everything gets a Unique Property Reference Number, or UPRN, a numeric identifier conjured up for every addressable location in Great Britain. If you pay up and subscribe they'll tell you what each 11-digit number represents, but anyone can check where they are and so determine the administrative area and the postcode. The road gantry by the 3B's cafe, for example, has a UPRN of 10001273135 which relates to a postcode of TW16 5LN and is definitely in Hounslow.
If you'd like to see a map of all the addressable locations in TW16 and in London, of which there are 18, I've made a Google map to show you. This is what postcode districts technically look like, a set of points not a contiguous area. The TW16/London overlap is a bit of a mess and splits across three separate locations - mostly near the 3B's cafe but also a couple of points close to BP HQ in Sunbury and also three on Lower Hampton Road between the reservoirs and the Thames. I even trooped over to Lower Hampton Road to have a look and can confirm that 10025171343 is an electricity substation, very marginally inside Richmond upon Thames, and not worth trooping over to.
To round off this round-up, let's return to that list of questionable postcode districts I mentioned at the top of the post. Thanks to Ollie's official database extract I can confirm that IG10 and KT21 have no addressable locations within the Greater London borough so officially do not enter London. It's good to clear that up. KT7 has three isolated addressable locations at Kingston Delivery Office, but I said non-geographic postcodes didn't count so I'm discounting that. Which leaves KT10, RM19, SL0, SL3 and WD19, each of which have addressable locations but not addresses inside the Greater London boundary. I've made you a separate Google map to show you those.
Offically in London if you count addressable locations
• KT10(2 UPRNs): Two ends of a footpath between Merritt Gardens Park and the Esher Bypass on the western edge of Chessington. Publicly accessible. I have never been.
• RM19(1 UPRN): A pond within Wennington Marshes Nature Reserve. Not publicly accessible. Off Coldharbour Lane (publicly accessible). Arguably the remotest spot in London. If you've walked section 24 of the London Loop you've been close.
• SL0(3 UPRNs): A footbridge over the River Colne, the car park by Little Britain lake and a footbridge over the Slough Canal Arm. All near Cowley. If you've walked section 11 of the London Loop you've beeen to all three of them.
• SL3(14 UPRNs): A spread of locations along (and close to) the M25 between junctions 14 and 15. Includes the edge of Harmondsworth Moor, a bridge on Bath Road and the westernmost point in London. I visited last month, coincidentally, after leaving the Heathrow Biodiversity Site.
• WD19(3 UPRNs): Two ends of a footpath between South Oxhey and Pinner Wood, plus a gate on a footpath between South Oxhey and Hatch End. If you've walked section 14 of the London Loop you've been to the first two and if you've walked section 15 you've passed through the other.
Which means, finally, I can clear up the conundrum of which postcode districts are in London are which aren't. This should be a definitive list.
In summary, 190 postcode districts are wholly within Greater London, another 24 postcode districts are mostly within Greater London and 30 postcode districts are marginally in Greater London. That's a grand total of 244, i.e. to visit every postcode district in London you have to tick off all 244 of them. Additionally 5 postcode districts are technically in Greater London but have no overlapping addresses, only addressable locations.
