Mileson Horton, born 1899. Amazingly, that's all I can find about him apart from the fact that he wrote for early television and seems to have specialised in crime stories. Quite what he would have been contributing to Swift Annual 1 (1954) I don't know.
Horton, at the time working as an insurance clerk, was the originator of Photocrime a series of fumetti-style murder mystery stories told in photographs and captions originally published in Weekly Illustrated in 1935. These proved so popular that a summer break caused a torrent of reader complaints. The series was syndicated in America by the Des Moines Register & Tribune and a book appeared in 1936, co-written by Thomas Pemberton, the pen-name of Sir Henry Thomas Hopkinson, one-time editor of Picture Post.
Horton is also notable as the main author of the first multi-episodic show specifically written for British television. The show was called Telecrime, the first series of which began broadcasting live from Alexandra Palace on 10 August 1938. Each show ran for five ten- or twenty-minute episodes but the series was cut short when the BBC stopped broadcasting television during the Second World War. Telecrime—or Telecrimes as it became—returned in 1946 for a 12-episode run. Horton followed it with another series of 15-minute adventures with a similar premise entitled Be Your Own Detective, broadcast as part of the Kaleidoscope TV magazine in 1947.
Apart from a handful of radio plays and a book in the late 1940s, I find no further trace of him bar that one contribution to Swift Annual in 1954 when he was in his mid-fifties.
'Mileson' is such an odd Christian name, I'm wondering whether it was a pen-name or perhaps a middle name, which could explain why there is no trace of him in birth records or on the 1901 census.
Photocrimes, with Thomas Pembroke. London, A. Barker, 1936; New York, Hillman-Curl, 1937.
Be Your Own Detective. 15 Mysteries for you to solve, photographs by James Maycock. London, Fenmore Publications, Jul 1948.
__The Back-Stage Murder, with H. T. Hopkinson (from 10 Aug 1938)
__The Fletcher Case (from 24 Feb 1939)
__The Almost Perfect Murder (from 15 Apr 1939)
__Circumstantial Evidence (from 25 Jul 1939)
Telecrimes (12 eps., 22 Oct-25 Nov 1946)
Be Your Own Detective (Kaleidoscope; 1947)
Inspector Cobb Remembers (series):
__5: The Case of the Twin Sisters (General Forces Programme, 29 Jan 1945)
Professor Burnside Investigates (series):
__1: The Case of the Fifteen Coppers (General Forces Programme, 11 Jun 1945)
__2: The Case of the Traveller's Wife (General Forces Programme, 19, Jun 1945)
__3: The Case of the Stolen Payroll (General Forces Programme, 28, Jun 1945)
__4: The Case of the Final Dividend (General Forces Programme, 2 Jul 1945)
__5: The Case of the Murdered Mariner (General Forces Programme, 10 Jul 1945)
__6: The Case of the Lonely Spinster (General Forces Programme, 17 Jul 1945)
Appointment with Fear (series):
__Death Takes a Honeymoon, with W. L. Catchpole (Light Programme, 14 May 1946)
__Escape to Death (Light Programme, 25 Dec 1946)
Dead Men (Home Service, 2 Apr 1947).
The Servant Died at Midnight (Home Service, 7 May 1947)
The Man With the Twisted Neck (Light Programme, 16 Mar 1948)
Death Takes a Honeymoon (Appointment With Fear, ed. Ronald Flatteau, Fenmore Publications, 1948)
UPDATE: 25 September 2009
Thanks to the discovery by Leonardo De Sá of a feature on the Photocrime phenomenon in Life magazine (see comments), I've managed to—perhaps—discover the real identity of Mileson Horton. Life refers to the author of the series as Denis Horton and a quick search of birth records reveals a Dennis (sic) James F. Horton born in Lambeth in the first quarter of 1899, the year in which Mileson Horton is supposed to have been born.
Tracking him further is a little more problematical. There was a Dennis Jas. Horton who served with the Essex Regiment in the Great War who might be him.
As Denis J. F. Horton, he married Edith M. Mileson in Surrey in 1951, whom I believe is possibly Edith Minnie Mileson, born in Essex in 1900. Now, he was using the name Mileson Horton many years earlier... so what their earlier connection was I've no idea. A long-time family friend? A collaborator? Who knows.
Horton died in Worthing in 1964.
I've updated the checklist of his work to include a few more radio plays I've discovered since the original piece.