Ian Billings (Norvic Philatelics) reports on the Delphi Forum The Virtual Stamp Club.
A nice find for one lucky collector. An Anniversary Prestige Stamp book with 5 panes of stamps instead of 4!
"The lucky collector received two books from Royal Mail's Philatelic Bureau, and one book had 2 sheets of pane 3, the se-tenant Arnold Machin and 4d brown Machin commemorative stamps.
A second report (also from Ian)
"A dealer has reported a different error on the same book.
In a sealed pack of 10 books from the Bureau, one book had Pane 2 duplicated. This is the pane with 2 x £1 stamps in, so he gets £2 extra value!"
"Sounds like sloppy work from De La Rue Security Print, and we should expect more reports."