Royal Mail Heritage: Mail By Air
   First UK aerial, 1911
   Military mail flight, 1919
   International airmail, 1933
   Domestic airmail, 1934
   Flying boat airmail, 1937
   Datapost service, 1980s


different imprints: 1st Class up to 100g / 1st Large up to 100g / Euro 20g World 10g / Worldwide up to 10g / Worldwide up to 20g / Worldwide up to 40g / 1L / 1LG / A Letter / 1L Signed For / 1LG Signed For / SD1