1st class gold Machin security stamp from retail book of 12, 2012, coded M12L MTIL.
This surprise discovery is the 1st class gold from booklet of 12, coded MTIL M12L, first discovered in April 2012, after the issue of the Diamond Jubilee booklet of 12.
This is the only 1st gold stamp with 2012 coding, all other 1st class stamps being Diamond Jubilee, until the Royal Mail Red stamps were issued on 3 January 2013 with 2012 year codes. As the 1st class Jubilee stamps had a different iridescent printing, the cylinder used for 2nd class books of 12 was probably also used for the 1st class books of 12. The booklet packing dates were 15/12/11, 20/12/11, 21/12/11 and 22/12/11 indicating quite a large printing.
However, as far as we know these were never sent to the Philatelic Bureau, and were only distributed by the Post Office supplies department to Post Office branches. Because of the larger-than-usual increase in postal tariffs in April 2012 stocks of definitive and country stamps were exhausted at many POs and Royal Mail Business Supplies at Edinburgh also had to cancel orders. Thus these are one of the early scarcities of modern booklet stamps.
SG U2968 - also used for other years