My mother recently found a letter from her favourite aunt which was sent on 3rd January (not sure what year but I'm pretty sure it was early 80's?). The envelope has a 1p stamp on it and the aunt made mention of having to get the letter off to avail of the 1p offer. Does anyone remember the reason for this special offer? I have a vague recollection of it but have googled and can't find reference to what the reason was. BTW the year is not readable on the envelope.