May 1, letter sheet, A27, turned inside-out and used from London to Duffield, showing superb strike of the red London "PAID" 'tombstone' datestamp of 1 May 1840 and faint black "Temple/1D. PAID", inscribed "Paid" at lower left, then turned and re-used locally in Derby showing light but readable "DERBY/MY 2/1840" double-arc datestamp and rated "2" in manuscript; vertical crease. An extremely rare and most unusual pre-official usage date cover. B.P.A. Certificate (1997). Photo