[HPFGU-OTChatter] UK postcodes: The intrigue!

[Kathryn Cawte]

Tabouli wrote -
Ah yes, David and all ye British folk...
 
While we're on the subject of UK addresses, something that has always
perplexed me is those double barrelled postcodes like BS23 3JL.  How do they
work?  I've figured out that the 2 letter code in the first bit is an
abbreviation of the county, but what's the rest?  Do they divide the county
up into bits and number them?  What's with the other bit then, the suburb
code?
 
I also notice that Canada has similar postcodes.  What's the story there?
 
Tabouli.
 
 The first two letters refer to the town usually or sometimes a nearby town.
OK that's confusing - so for example my postcode starts SL 
even though I live in Windsor because we come under Slough for postal
purposes because Windsor's not all that big. The next number is a code
usually based on a section of a town, a specific suburb, a village etc. No
way you can tell where unless you are a postman or something. then
the final part is a street code. When I order something by mail order or
order pizza they generally take the postcode and their computer will 
give them most of my address so I just need to give a house number.

The exception (slightly) is London where instead of referring to the city
the first bit refers to a section of the city. eg SW for South West. 
Street signs in 
London tend to have the first half of the post code on them - sort of an aid
to navigation. Although Londoners do identify their address by 
borough when talking you're just as likely to hear someone say "I live in
SW1" or whatever - not being a Londoner I don't actually
know exactly where that is but you get the idea.

I assume Canadian postcodes work on the same principle since they're very
British in many ways.

K