Great Britain Queen Elizabeth II 1966 4d Battle of Hastings, SG705ab.
A superb unmounted full original gum top marginal imperforate block of twelve from the top two rows of the sheet, containing two imperforate strips of six.
A rare and desirable modern GB stamp error with only one sheet of twenty strips discovered. SG705ab.
The Stanley Gibbons catalogue price for a strip of six is £3,500 meaning no premium is attached to the price for the additional rarity factor in being a block of twelve.