HERE IS A MAJOR STAMP  ERROR FOR GREAT BRITAIN ROYAL POSTAGE. A QUEEN VICTORIA
REVENUE PATENT COMMISIONERS OFFICE STAMP. IT IS A  4d  1872 STAMP WITH MAJOR AND MINOR POSTAL STAMP ERRORS. THE   RED OVERPRINT SAYS "COMMISSIONERS OF PATENTS FOR INVENTIONS". HOWEVER... ERROR (1)...THE ROYAL  BRITISH CROWN  IS INVERTED (UPSIDE DOWN)... THIS IS A MAJOR BRITISH  POSTAL STAMP ERROR. ... ERROR (2) : ...THE RED OVERPRINT WORD "FOR" IS  MISPRINTED. IT IS A  TYPE LETTERING DOUBLING ERROR. SEE PICTURE CLOSEUP. AN EXTREMELY RARE  GREAT GREAT BRITAIN STAMP FOR THE  ERROR PHILEATLIST. SELLER GUARANTEES AUTHENTICITY OR REFUND.