Spectacular perforation error on Lord Mayor's Pane!!

Previously we have reported many errors in Prestige Books involving duplicate panes, most notably on the 2007 Machin Anniversary book, which exists with each of the panes duplicated in different books.

But now for something completely different. A collector in Hampshire bought the Treasures of the Archive PSB to prepare his own FDCs and found to his amazement that the Lord Mayor's pane of 4 x 20p stamps - the lowest value pane in the book - was doubly perforated! The effect of the mis-perf is that the vertical perforations are continuous and the stamps are only held in place by the horizontal teeth.

It's well known that these are printed in larger press-sheets (of 12-18, we think) so as usual, we'd be interested to know of any others that have been found, so that the finder has some idea of the scarcity of the error.

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