Postcodes in the UK are pretty specific — a postcode such as “SE1 6AD” will often identify one or a few specific buildings, unlike countries where a postcode represents an entire neighbourhood.
This leads to an interesting question: how short can you get an address and still have Royal Mail deliver post there?
To figure this out, I decided to find the most minimal way to write my home address, send myself a letter using that address, and see what happens.