Lot 50151 – 1959 “Dollis Hill Phosphor Trial” on 3d deep violet Wilding in lower right corner marginal block of 6

1959 “Dollis Hill Phosphor Trial” on 3d deep violet Wilding in lower right corner marginal block of 6 (2×3), with the left hand column showing two 1 1/2mm blue phosphor side bands and the second column with a 1 1/2mm blue phosphor left band, both printed under the ink, very fine and scarce (SG Spec ST7(4)a & 7b, £1’800+)

Note: For more information on these trials, see “The Dollis Hill Find: Mechanisation of the Mail and Phosphor Trials on Wilding Portrait Stamps” by Edward Klempka, available from the GB Philatelic Society