How long is a letter delayed if you leave the postcode out?

Question

just a general wondering, I sent my friend a card and couldn't recall their postcode (I live in the UK). I sent it on thursday 26th June first class and they don't seem to have gotten it yet. So on average, how long does a letter get delayed if the postcode is left off (the address was correct)?

Answer 1

In the U.S., it is not delayed.