How do the UK postcodes work?

Travel Info
I know they're nothing like the american five digit numerical ones.

Travel Tips

The first two letters refer to a town, except in London where they are compass points (e.g. a typical London code is W12 7RJ - that'll get your post to the BBC).

A typical code outside London would be BD1 3AB, where BD = BradforD. The areas are then subdivided into smaller sections, where in our example BD1 would be central Bradford, and BD22 could be a village half an hour away from the centre.

The second half of the postcode takes it down to street level. Usually, there will be two postcodes per street - one for the evens, and one for the odds. Longer streets may have multiple postcodes.

In most cases, the post office will be able to deliver letters given only a house number and postcode.