19 February 2015 - Machin definitives from Inventive Britain PSB
The Inventive Britain stamp issue included a prestige stamp book containing 12 special stamps and a pane of 8 x Machin definitives - 2 x 1p, 3 x 2p, 1 x 81p, 2 x 97p. Although issued in 2015 these were printed in 2014 and have security codes MPIL M14L.
The 81p was printed in turquoise-green instead of emerald green due to an error by printers Cartor. But as the entire print run was wrong, this does not make it any scarcer. (The image gallery includes a comparison with the 81p sheet stamp in emerald green).
This is the 1p stamp from the pane with Norvic catalogue number 4001P.4