Great Britain 1840 1d Mulready Envelope First Day of Issue (Forme 1, Stereo A6), SGME1Great Britain 1840 1d Mulready Envelope First Day of Issue (Forme 1, Stereo A6), SGME1. Sent from London to the addressee in Topsham on May 6th 1840, the first official day of use, B Borough 6 MY 6 1840 date stamp in red on reverse. A fine quality example (many other examples are heavily soiled) with a neat cancellation by a crisp strike of an orange red Maltese Cross. Mulready stationery letter sheets were introduced as part of the British Post