1969 Jersey 10s "Royal Court". A superb unmounted o.g. example of this very rare error of colour with the border printed in green instead of slate blue. A magnificent example of this key Jersey rarity, that occurred when during the final printing one sheet of 25 was accidently fed into the press which had been set up with the green background of the 50p value. Offered with a normal for comparison. 1999 BPA Cert.