Great Britain Philatelic Society

Is there a definitive answer, whether the GVI £1 stamps were only valid until 29.02.1972 or are they still valid like the early EII Castles? I have a registered cover from late September 1990 with the GVI £1 brown paying some of the £1.75 reg fee and 97p in decimal stamps slightly underpaying the 26p postage to Germany. The Michel specialised GB catalogue claims that all pre GV/EVIII/GVI stamps were only valid until the end of the decimalisation switchover.
Thanks
James

Yeah, Michel have it right. According to the Post Office Scheme taking effect 1 March 1972 that covered the demonetisation by redefining what was valid for postage (see https://www.gbps.org.uk/po-schemes/inland.php):

(3) Payment of postage or fees payable under these regulations may be denoted:
(a) by adhesive postage stamps bearing the effigy of Her Majesty Queen Elizabeth the Second, being stamps of denominations of money in the new currency of the United Kingdom provided for by the Decimal Currency Act 1967;

In other words, only QEII stamps, but the 1955-71 pound values counted because a pound was still a denomination in decimal currency.

By 1990 I should think it was so rare for anyone to use a KGVI £1 that there was a good chance that the clerk would have no idea that it wasn't supposed to be valid!

thanks mate!