What this is saying is that the US zip code system is broken
The "Z" in ZIP is "Zone." If ZIP Codes were supposed to line up with cities, they'd be called CIP Codes.
compared to other countries' postcode system
And by that you mean "compared with the single small area of the country in which I live, which somehow makes me an expert of every method of routing mail in every one of the 200+ nations on the planet."
here in the UK the first part of a postcode is almost always a two letter code for a town or city
The first part of some of your UK Post Codes don't indicate a town or a city. They indicate a nation, like JEn for Jersey.
then a number for the large area within it
Which is not always true. PCRN and ASCN are UK Post Codes, but have no trailing numbers.
London is so big and densely populated that it has multiple virtual town codes allocated to different areas
In the U.S. if the address density gets too high, we just roll out another ZIP Code. I used to work in a building that had enough offices that the building had its own ZIP Code. No need to confuse people by inventing imaginary towns like in London.
Are you sure your country's post code system isn't the one that's broken?
(There are better counterexamples but I don't think it's relevant.)
London's codes aren't "virtual", they stand for North, North East, East etc.
I think the British system is a bit more human friendly, as the letters are usually mnemonics for large towns or areas, and just 5-7 characters is specific to about 20 addresses. (It can be a single business within a building, or apartments on 2-3 floors.) However, just like ZIP codes the boundaries don't align to political regions.
The over-verification problem would be surprising in Britain due to the codes being very specific, the whole address is easily verified. Usually this works the other way around — you type in the postcode first, and select from the 20 or so full addresses within it.
The most common problem is new addresses not being in the database used by a website, and them not allowing manual entry.
The "Z" in ZIP is "Zone." If ZIP Codes were supposed to line up with cities, they'd be called CIP Codes.
compared to other countries' postcode system
And by that you mean "compared with the single small area of the country in which I live, which somehow makes me an expert of every method of routing mail in every one of the 200+ nations on the planet."
here in the UK the first part of a postcode is almost always a two letter code for a town or city
The first part of some of your UK Post Codes don't indicate a town or a city. They indicate a nation, like JEn for Jersey.
then a number for the large area within it
Which is not always true. PCRN and ASCN are UK Post Codes, but have no trailing numbers.
London is so big and densely populated that it has multiple virtual town codes allocated to different areas
In the U.S. if the address density gets too high, we just roll out another ZIP Code. I used to work in a building that had enough offices that the building had its own ZIP Code. No need to confuse people by inventing imaginary towns like in London.
Are you sure your country's post code system isn't the one that's broken?