[theBobBob]

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.

[lblume]

Why not?

[Macha]

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.

[flashpoint31415]

This is delightfully referenced as the Blind Letter Office in Terry Pratchett's book "Making Money":

<Moist ran downstairs and Lord Vetinari was indeed sitting in the Blind Letter Office with his boots on a desk, a sheaf of letters in his hand and a smile on his face.

'Ah, Lipwig,' he said, waving the grubby envelopes. 'Wonderful stuff! Better than the crossword! I like this one: "Duzbuns Hopsit pfarmerrsc". I've put the correct address underneath.' He passed the letter over to Moist.

He had written: K. Whistler, Baker, 3 Pigsty Hill.

'There are three bakeries in the city that could be said to be opposite a pharmacy,' said Vetinari, 'but Whistler does those rather good curly buns that regrettably look as though a dog has just done his business on your plate and somehow managed to add a blob of icing.'>