Comment by philo23

1 month ago

Kinda meta, but this is the first time in a long time where I've put only the first half of my postcode in expecting it not to work and been surprised. Most of these "find your nearest XYZ" site require the full postcode which is just unnecessary unless you're looking for a fairly precise location. A full postcode can narrow your location down to an individual street, so its nice not to give too much away if you can.

For anyone not in the know, UK postcodes are made up of two parts: a general area (the outward code) and then a more specific one (the inward code.) Generally speaking a postcode + house number will be good enough to get a letter delivered to the right place, though the sorting office might not be too happy with you...

The format [0] is roughly: AB12 3CD, though the number of letters/numbers on the left side can vary a bit. As far as I know the second set of numbers is always 1 digit though, so that's how you can easily split the two sides of it to format it nicely. There's a couple of special ones that break the rules though.

[0] https://en.wikipedia.org/wiki/Postcodes_in_the_United_Kingdo...

I agree with the bit about the having to enter a full postcode on some sites, I often use one nearby or, if they make me select a specific address for no valid reason I make sure I use a random address nearby. Apologies to some of my neighbours who might be bombarded with junk mail for services I’ve once been half interested in.

A full postcode is often much less than a single street.

Picking something at random stick “SW15 6DZ” into Google maps and you’ll see it only covers 6 buildings (most are individual houses but some are split into flats). According to the Royal Mail address finder site there are only 12 unique delivery addresses that share that postcode. The Western half of that road has 12 or so full postcodes for only 100 houses.

A full postcode and one other bit of information can often be enough to uniquely identify someone.

If a US 5 digit zipcode is roughly equivalent to the “general area” part of a UK postcode (94107 <=> SW15) then the full UK postcode is like the 9 digit US Zip+4 format where the extra 4 digits narrow location down to a block, part of a block or even a specific building.

  • A friend of mine who lived in a tent in a park got his own postcode. True story.

    Details: election time. He went to the election folks and asked for his election papers. They said "sure, where do you live?" he said "the Bender, Eastville Park, Bristol", they said "that's not a valid address", he said "that's where I live, so that's where I'd like my registration to be, please". There was some back and forth. They caved, and duly entered his address on the electoral roll as such. Then he went to the Post Office and said "this is my address, as entered on the electoral roll, can I have my postcode please?". The Post Office kinda had no option, since this was now his official address. So they gave him a postcode and the postie had to walk through the park to drop off his mail.

    • The post office will attempt to deliver if you put an address on it.

      There is guy living off grid in I believe Dorset on YouTube called "Maximus Ironthumper". The post office told him to try sending himself letters, eventually they started turning up. Then that became the address.

      He has a whole series of videos about how he kinda managed to setup his off grid living situation, there is everything from how to avoid planning permission, to how he setup his solar power.

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    • I believe similar has happened, whereby a seller of the Big Issue (a magazine sold by the homeless to raise money) had a postcode issued to a bench where they could pick up deliveries of the magazine.

  • "A full postcode is often much less than a single street."

    My business has its own unique postcode and so does next door! Between us we cover roughly three acres. Our place is one building with parking and a fair bit of greenery.

    • There is apparently a suite to rent in the Rosewood Hotel in London (near Holborn) which has it's own postcode (WC1V 7EN).

      To be fair it's a 6-bedroom wing, but still a fun fact.

  • The concept of a postcode was originally due to the sack weight a postie could deliver before returning to the van.

    Each postcode would then have an optimum delivery route often devised by the postie's themselves.

  • > the 9 digit US Zip+4 format where the extra 4 digits narrow location down to a block, part of a block or even a specific building.

    A US Zip+4 usually identifies a specific delivery point. In some places this can mean it can even identify specific units within a building.

  • Mail from a guy that wants to preserve pubs wouldn't be junk.

    • How is that different from a mail from a local church asking me to donate, or a local bingo club opening a new location - it's all junk. If I didn't ask for it to be sent to my address, it's all junk.

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    • Any communication received without explicit consent, after providing details, is junk, and would fall under GDPR as using that info for a different purpose than what was described.

  • Yep, locally where I am there’s one postcode for all the houses on one side of the street (all the even numbered houses) and another for the opposite side (all the odd numbers.)

    Presumably it helps a lot with validating the address is correct, kinda like a checksum, and also probably helps with how deliveries are organised by the local office before the postie is sent out with them all.

In Ireland we were very late to the postcode game and when we introduced them a few years back they actually uniquely identifies a single address. We also continued our "interesting" habit of renaming everything to make them sound more Irish so they are called Eircodes. In theory you could just put the single 7 character Eircode on a letter and it would be enough although our postal service has said we can't do that.

  • Why not?

    • By being late to computerized sorting, the postal service (An Post) never actually needed postcodes the way others did, as by the time they got computerized, fuzzy address lookups in the full address database was something that was available. It's mostly the third party couriers and marketing people pushed for post codes so they could apply techniques from other countries here.

      Now asking An Post to overhaul their system to work on postcodes only is a bit like asking a postal service which requires postcodes to make them optional. It's technically possible, sure, but they're not going to want to spend the money.

      _That said_, An Post's last resort routing department is pretty famous for getting the right address from pretty fragmentary information like "Mary down by the church, formerly of Kilnowhere", so I'm sure if a letter with just a eircode arrived there they'd sort it, but I imagine that An Post don't want to encourage people doing things that increases load on the labour intensive sorting.

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There used to be a site "postcodeine" which would overlay the prefixes onto a map as you typed, so you could enter "SW" or "KY" etc and watch it narrow down the area by keystroke.

> A full postcode can narrow your location down to an individual street,

Often a single block of flats. Rurally perhaps even just a single residence?

I lived in SW1 many years ago and was surprised to learn, from this website, that SW goes all the way out to SW19!

  • Fun fact: apart from the main office SW1 they're alphabetised by area, from SW2 Brixton to SW19 Wimbledon. All of the London postcode areas are like this.

    • Hadn't noticed that before.

      https://en.wikipedia.org/wiki/SW_postcode_area

      SW2 to SW9 are in alphabetical order: Brixton, Chelsea, Clapham, Earls Court, Fulham, South Ken, South Lambeth, Stockwell.

      But then it starts again and you have to squint a bit for SW10-SW20: Brompton, Battersea, Balham, Barnes, Mortlake, Putney, Streatham, Tooting, Wandsworth, Wimbledon, West Wimbledon.

      Looking at a few others (SE, etc) I see that the first chunk of them are in alphabetical order, but then they've added some extra ones later that break the ordering (e.g. SE19 onwards) but they have tried to add the extra ones in mostly alphabetical order too.

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  • And a bit further to SW20 in Raynes Park (a.k.a. “West Wimbledon” in Estate Agent vernacular).

    I’ve lived somewhere in SW18/SW15/SW19 for the last 30 years. Having not grown up in London I can’t imagine living anywhere else. Apparently many other bits of London (North, East, central, etc) are good too but I’m not ready for change.