If you are ever desperately bored, and you want to know exactly how the Royal Mail stores and processes UK addresses, then go here:
https://www.poweredbypaf.com/using-our-address-data/use-the-data-yourself/
and download the 237 page PDF in the link “Download the programmer’s guide”
which I had to do for a web-based database system I wrote for a client. Go on, I don’t see why I should be the only one who had to suffer 
Purely as a show of support I should go read it.
The '‘postal town’, for a small settlement, provides the Post Office with the correct sorting office that they will send the mail to before preparing it for local delivery. The one for Brookwood is WOKING, but it doesn’t mean Brookwood is a political subdivision of Woking. If you put GUILDFORD which is arguably almost as close, there will probably be a delay before it gets redirected. In some sparsely populated areas the postal town may be a long way away. And the postcode may even be based on the initials of a completely different town.
It’s no longer necessary to include the county as the postcode does the job instead, though some older people include it anyway.
What kind of names?
Currently, the US Postal Service strongly advises against underlining in addresses.
Apparently, this tends to confuse the Optical Character Reader software that scans the envelope, identifies the address, and imprints the full delivery point barcode on the bottom. These automated scanners process most of the mail. If your envelope can’t be read by the automated scanners, it gets pulled out for manual processing. This could delay your letter for a bit, maybe up to a day longer. But it should still get there. If it’s going from the USA to a foreign country, probably all the USPS does is route it to a batch going to the United kingdom – once it gets there, the UK Postal Authorities deliver it the rest of the way.
Then again, one picture *is *worth a thousand words.
I’ll be here all week. Try the veal. 
This is substantially US practice as well for sparse areas.
Unsurprisingly since the underlying problem is the same: distribute stuff to a wide area efficiently where political divisions are essentially irrelevant other than as names.
It’s not a game: it a difference between the way UK addresses work and American (and Australian) addresses work.
Australia uses zip codes. A zip code more-or-less corresponded to a mail bag in the even older aus system. Everything with the same zip code sorted to the same bag, which would then be sorted for delivery. Aus now uses “delivery point” codes internally instead of zip codes, because “a mail bag” is no longer a useful sorting system.
The UK system is closer to a “deliver point” number than it is to a typical American zip code. A delivery point number is a complete address: a UK postcode is an almost complete address. The UK is unusual in exposing to the public the fine-grained internal-use mail code – that causes some problems for the post office, because it means internally they are locked into using the same system that the public uses. Internally for the post office, it’s like you could never change your address, because you would never be able to get mail again.
That makes no sense at all for me. My address is where I live; if I moved to another house, that would have its own address.
Postcodes have become ingrained into British life in a way never envisaged by the originators nearly 60 years ago. Some big cities already had divisions (N, S, SW, etc) but this went a lot further. The idea was simply to make sorting by machine easier, but it wasn’t long before insurance companies realised that they were a good way to divide the country up into risk areas. Now, everyone who uses satellite navigation uses the postcode as a convenient way to enter a destination.
On my parents street, which is in a small English village, the first 10 houses have names, and the houses are written like ‘Moss House, New Street’, then the street inexplicably adds a name, and the next house on the street is ‘1 Mayfield, New Street’, the ‘Mayfield’ houses go up to 15, then it gets dropped, with the next house, halfway up the street, being, finally, ‘1 New Street’. We had to redeliver a lot of post living there, every time they get a new postie. Even by English standards their street’s confusing.
I actually worked in a UK sorting office as a Christmas temp a couple of years ago, and overseas stuff arrived with almost every permutation of ‘England’, ‘UK’, ‘GB’, ‘Britain’, ‘Angleterre’ etc that you could think of, though I don’t think I saw ‘Great Britain and Northern Ireland’ on any parcel.
The dumb thing I saw most often was people posting from the UK to the US (and one to Australia) using just the state abbreviation, with no ‘USA’ (or ‘Australia’) written anywhere on the packet. Well, and the cards addressed to ‘Bob and Mary’ with no further details.
Melbourne writes:
> The UK system is closer to a “deliver point” number than it is to a typical American zip code.
It depends whether you’re talking about a five-digit American zip code or a nine-digit one. Some people in the U.S. only use the first five digits of the zip code. That system began in 1963. Before then, in some big cities, there was a system just for that city where you put a number between the city name and the state name. The U.S. Post Office decided that this wasn’t good enough, so they began the five-digit zip codes in 1963. The five-digit zip code more or less identifies where your local post office is. In 1983 the nine-digit zip code system began to be used. The nine-digit zip codes gets an address down to a much smaller region. Some people don’t bother with the last four digits of those nine digits. So the three systems are:
Urbanville 9, State (until 1963)
Urbanville, State 99999 (1963 to 1983)
Urbanville, State 99999-9999 (1983 to present)
UK is fine in the US. I’ve always sent my mail that way (perhaps marking it “United Kingdom” if I was feeling particularly verbose.) It’s apparently the standard United States Postal Abbreviation for Great Britain..
IMO Wendell’s earlier reference to “games” was about the idea of users deliberately providing the minimum possible information to the post office, rather than providing a full address with all the redundant (and potentially conflicting) information.
Yes, one could address a letter to Person Name
PostalCode
Countryand have some expectation of it arriving in the right place eventually. But that’d be playing games with the post office(s), not using the system as it was intended.
Continuing Wendell’s explanation of US zip codes …
As a practical example:
My city of ~80,000 people is divided into two 5-digit zip codes. I live in a condo building. It’s a single contiguous building with 94 apartments. The 94 apartments comprise 12 separate 9-digit zip codes. My particular 9-digit code represents 10 apartments and about 5 frontage feet in our communal wall of mailboxes.
So US practice is quite like UK practice, where the full zip code is a delivery point. Where we differ is that to ease the initial transition back in 1983, the authorities made the last 4 digits optional. So being the terminally lazy and conservative sorts 'Merkins are, the public utterly ignores the last 4.
bob++ just said something I’d never thought of. Which may be the key to getting 'Merkins to start using the full 9-digit zip. That is, using the full delivery point code as shorthand for an address when entering it into a phone, GPS, etc.
I just tested that idea. Both Google maps and Bing maps do not respond to a full 9-digit zip. At least not in my area. Google maps draws the 5-digit zip boundary and centers the view on it. Bing maps just drops a pin on the centroid and centers there. Both apps ignore the last 4 digits. The navigation app on my Android phone is based on Google maps and does the same.
It seems we’ve got a ways to go yet with this solution.
The most critical parts of a UK postal address are the street address and the postcode - in fact, they’re the only truly necessary parts - postcode denotes a unit about the size of an average street (some streets span multiple postcodes) - and house number/name + postcode represents a unique address.
So you can reliably get a letter, inland, to its destination with literally just the house number and the postcode (yes, I have actually tested this - it works) - but more is better - and I wouldn’t want to try just house number, postcode and UK from overseas.
A ‘full’ address would normally be:
Addressee name
House number/name and street/road name
Town or district
Postal City
Postcode
Country
It used to be the case that county was included between postal city and postcode, but Royal Mail (and other carriers who typically use the same address sources) dropped it some years ago.
Sometimes, you can get away with startlingly little by way of an address.
For example, Peterhouse, one of the colleges at Cambridge, has its own postcode. My brother, who got his PhD at Cambridge, tells me of a case where a letter was addressed to “name, CB2 1RD, England”, and reached the addressee promptly.
My mother once got a letter addressed like this:
Mona (her first name)
(zip code)
and nothing else. But it arrived, without apparent delay.
I guess it helps to live in a small town (12,000 people) for 70 years, and be active in civic life.
Lots of institutions in the UK have their own postcode - each of the Oxford and Cambridge colleges doed, I think. Sometimes a large institution will have separate postcodes for its different departments
Even if a postcode refers, as is more typical, to a group of houses, there’s every chance that the postman knows who lives in which house, and so a letter addressed to [name], [postcode] stands an excellent chance of being delivered with minimal or no delay.
I’ve done that experiment too. Seems to work OK as long as the recipient is receiving other mail (and so their name would be known to the person delivering the round that includes the postcode).
If you tried that with the name of a person who seldom receives postal mail, or has just recently moved into the area, the delivery would more likely fail.
I also did experiments to try to determine how small a postcard I could send (because the system specifies upper limits of size only). Postcards a little smaller than a business card arrived OK. Postcards the same size as the stamp, or twice the size of the stamp, never made it through the system.
I’m not sure I understand the need for the “Postal City” when a post code is listed*. Sure, more information is better but it seems overkill.
I’m not saying the US Post Office way of doing things is better but the equivalent in the USA of the UK address would be like adding in the name of the regional sorting center in the address (which we would never do because A: we don’t know what the sorting center is and, B: the zip code (postal code) sends the letter to the proper regional sorting center).
*I mean, I DO understand the need in the sense of… do it because that’s what the postal service wants.
The USA uses postal cities too. The “city” on a US mailing address is just an alias for a Zip Code. It’s usually, but not always, the name of the post office that sorts your mail for delivery. It’s redundant because redundancy is good in addresses. Otherwise one transposed digit would make your mail undeliverable.
It’s just the backup for ambiguous handwriting; working in the central sorting office, we’d get handwritten postcodes that could have started with either B55 or BS5. One of those is in Birmingham, one is in Bristol. It should make it either way, but if the people doing the sorting (and the machine would definitely spit that one out, so it would be hand sorted) can’t tell which it is from the rest of the address, it’d go in the ‘?’ pile either for someone who really knows the area concerned to look at, or have the street looked up; or the sorter might guess, stick it in the appropriate slot, and maybe sent it on a pointless round trip if they guess wrong. It’s likely to take a day or so longer either way, unless the sorter guessed right, which could be cut out if the person had just written the city on.
I got the impression that most delivery mix-ups happen at the city level, as the closer the letter gets to the destination, the more the people dealing with it know the area. Even only working for a month as a temp, I got to know several of the typical local misspellings, uses of old discontinued postcode regions and other assorted common errors for the area I was working with.
I mean, you can play this sort of stuff (Irish postal service, not English), and it’s quite funny, but not if you want to get stuff delivered in a reasonable time.