1958-65 Wilding "Dollis Hill" Phosphor Trial 2d Light red brown on gummed unwatermarked specially prepared handmade paper, with all over yellow phosphor showing a strong phosphor response, very fine. Note: Experiments with yellow phosphor were short lived due to fears of toxicity of the phosphor ink. (SG Spec. ST5(4), £550) (Image)

1958-65 Wilding 3d deep lilac in mint nh partially perforated booklet pane of six (three stamps imperf on two side and three imperf on one side), perf. splitting between third and fourth stamp, otherwise fine and rare, cert BPA (2005) (SG £4'000 in 2019) (Image)

1959 "Dollis Hill Phosphor Trial" on 3d deep violet Wilding in lower right corner marginal block of 6 (2x3), 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
1959 3d Deep violet €œDollis Hill Phosphor Trial€œ. Very fine corner marginal perforated block of six on gummed crowns watermarked (upright) paper, the left hand column with two 11/2mm blue phosphor side bands and the second column with a 11/2mm blue phosphor left band, printed under the ink. Scarce. Spec. ST7(4)a/b. (Image)

1961 Parliamentary Conference 1s3d with ERROR BLUE OMITTED (Queen's head) in mint nh right marginal strip of three with centre stamp showing blue partially omitted, one of the rarest modern errors, with only 6 mint examples known of which 2 are damaged, an important showpiece (SG £40'000) (Image)

1962 National Productivity Year 3d mint with ERROR LIGHT BLUE OMITTED (Queen's head) in mint nh right hand marginal example showing central sheet marking, incl. normal for comparison, a lovely positional example of this visual error (SG £5'750) (Image)

1963 Paris Postal Conference Centenary 6d with ERROR GREEN OMITTED (leaves), mint nh, gum wrinkle, fine and very scarce, Pierron records only 30 mint examples, incl. normal for comparison (SG £5'500 in 2019) (Image)

1964 Botanical congress 9d essay depicting ferns and branch, printed in orange-vermilion, perf.15x14 on gummed unwatermarked paper, mounted on a Harrison & Sons presentation card, typed on reverse "Design No.32a./44069", an attractive and unique essay, ex Goaman archive (Image)

1964 Forth Road Bridge 3d showing variety IMPERF. BETWEEN SHEET MARGIN AT TOP, in mint nh vert. pair with normal, very fine and very scarce, Pierron records only 12 examples, cert. RPS (2014) (SG Spec. W54a) (Image)

1965 I.T.U. Centenary (ordinary paper) 1s6d with ERROR PINK OMITTED, mint nh right marginal, very fine and rare, Pierron records 21 mint examples, incl. normal for comparison (SG £4'000) (Image)

1966 World Cup (ordinary paper) set of three mint nh imperforate imprimaturs, right marginal examples, each stamp with a "BPMA" handstamp on reverse, very fine and scarce (Image)

1966 World cup (phosphor) 6d with BLACK OMITTED (Goalkeeper's hair and shirt) in mint nh left marginal horizontal strip of three showing a progressive omission of the black with a total omission on the left hand stamp, very fine and rare, Pierron records only 24 mint examples (SG £2'800+) (Image)

1966 British Birds (ordinary paper) 4d with ERROR RED OMITTED (Black Headed Gull's beak and leg & Robin's breast) on the vertical pair of a mint nh left hand marginal se-tenant block of six, nicely showing the normal stamps on the right vertical pair, very fine (SG £2'200+) (Image)

1966 British Birds 4d (ordinary paper) with ERROR RED OMITTED (affecting Black Headed Gull & Robin) in mintnh se-tenant right hand marginal block of four, very fine, a scarce and striking variety, incl. normal block for comparison (SG £2'200+ in 2019) (Image)

1966 British Birds 4d (ordinary paper) with ERROR EMERALD OMITTED (affecting Seagull, Blue tit, Robin) in mint nh se-tenant block of four, very fine (SG £600+ in 2019)
1966 4d British Birds. Very fine unmounted o.g. se-tenant block of four with emerald omitted, affecting Seagull, Blue tit, Robin. (Image)

1966 British Birds (ordinary paper) 4d se-tenant block of four with BRIGHT BLUE OMITTED, affecting the Blue Tit and the Gull stamps, very fine and striking variety, plus mint hinged normal block for comparison (SG £1'400+) (Image)

1966 World Cup Winners 4d on illustrated first day cover commemorating the England victory signed by the England team with Bobby Moore, Gordon Banks, Alan Ball, Geoff Hurst, Jackie Charlton, Bobby Charlton, Nobby Styles, Ray Wilson, George Cohen, Martin Peters and Roger Hunt, stamp tied by London machine cancel on first day of issue, very fine (Image)

1967 British Wild Flowers (phosphor) 4d with ERROR SLATE PURPLE OMITTED (Bramble on top left stamp) in mint nh left marginal se-tenant block of four, very fine and scarce, Pierron records only circa 50 mint blocks, incl. normal block for comparison (SG £500 in 2019) (Image)

1967-70 Machin 8d "Cambridge" colour trial in bright magenta, mint hr, pencilled "B" on reverse, very fine example of this unadopted colour which was produced in preparation for the decimal issue, very rare as Pierron records only four examples, incl. issued stamp for comparison (Image)

1968 British Paintings 1s9d mint nh with ERROR GOLD (Queen's head and face value), EMBOSSING & PHOSPHOR OMITTED, very fine, incl. normal for comparison, cert. BPA (2014) (SG £900) (Image)

1968 British Paintings 1s9d showing GOLD (Queen's head and face value), PHOSPHOR AND EMBOSSING OMITTED, mint nh right marginal, very fine and scarce, Pierron records 60 mint examples (SG £900) (Image)

1969 British Ships 5d with BLACK OMITTED (ship's hull, Queen's head, value and inscription) in mint nh right marginal single, very fine, offered with normal for comparison (SG £3'500 in 2019)
1969 5d British Ships. Superb unmounted o.g. right hand marginal example with black (Ship's hull, Queen's head, value and inscription) omitted. A spectacular and very visual error, offered with normal for comparison. (Image)

1969 Christmas 5d with green omitted (2nd shepherd's tunic), mint nh, very fine, incl. normal stamp for comparison (SG £375 in 2019) (Image)

1970 Anniversaries 5d with ERROR GOLD OMITTED (Queen's head) mint nh left marginal, very fine and rare, incl. normal for comparison (SG £3'500 in 2019) (Image)

1971 Paintings 9d with ERROR ORANGE OMITTED (Flowers) mint nh, couple of small wrinkles at left, fine and rare, Pierron records only 20 mint examples of this variety (SG £3'500 in 2019) (Image)

1971 Literary Anniversaries 5p with GOLD OMITTED (Queen's head), mint nh, very fine and rare, Pierron records only 36 mint examples, incl. normal for comparison (SG £1'200 in 2019) (Image)