As of 2018, documents that could shed light on his activities remain classified as "sensitive" by the Foreign and Commonwealth Office, under section 3(4) of the Public Records Act 1958.

He sustained disabling injuries to his knee and shrapnel wounds to the left side of his body which led to his being invalided out of the Army in 1917,[7] and for which he was awarded the Silver War Badge.

He joined the merchant navy in 1919, serving as a purser – first on a Scottish shipping line, then on a requisitioned German liner, SS Prinzessin, which sailed from London to Vancouver via South Africa, China and Japan.

[11] In 1925 Wilson answered an advertisement in The Times for a position as Professor of English Literature at Islamia College at the University of Punjab in Lahore (now part of Pakistan).

Wilson was interviewed and appointed by the college's principal, Abdullah Yusuf Ali, an author and educator who translated the Quran.

[13] Wilson provided a portrait of Abdullah in his second novel, The Devil's Cocktail (1928), as principal of the fictional Sheranwalla College in Lahore.

[7] En route to British India, Wilson met actress Dorothy Phyllis Wick (1893 – 1965) on the SS City of Nagpur, bound from Liverpool to Karachi.

Although a public wedding ceremony apparently took place at the Sacred Heart Cathedral, Lahore, no certificate has been found to confirm that a formal marriage occurred.

He set up and led Islamia College's University Training Corps and was appointed an honorary Major in the British Indian Army Reserve.

[citation needed] Wilson succeeded Yusuf Ali as ninth principal of Islamia College in November 1927 and resigned in March 1931.

[18] Crook suggests that Wilson's role at Islamia College may have been a cover for work conducted on behalf of British intelligence agencies as a recruiter and informant.

[4] The Soviet Comintern was active in subversion and insurrection, and the British authorities were combating an increasing number of terrorist plots and assassinations between 1928 and 1932.

Tunnel 51 and eight subsequent novels featured the struggle of Sir Leonard Wallace,[20] his intelligence officers and his agents against terrorism and subversion in the British Empire, the influence of the Soviet Union, the tentacles of global organised crime, and Nazi Germany.

From 1933 Wilson's publisher was Herbert Jenkins, and his novels included titles in the Sir Leonard Wallace series and others in the crime, romance, comedy and thriller genres.

[21] Wilson wrote "forceful, exciting, thrilling, vibrant, vivid, intriguing, daring" stories, according to reviewers in The Telegraph, The Observer, The Scotsman and The Times Literary Supplement.

In January 1940 The Observer's reviewer, Maurice Richardson, said Wallace Intervenes: "... is another spy story featuring Hitler in person, if not name.

This comes at the end of an exciting love-duel in which one of our younger agents has to seduce a beautiful Austrian Baroness, who fortunately turns out to be on our side all the time".

[11] And the only photograph that Michael had of Alec Wilson showed him wearing the uniform of an Officer in one of the Punjab Regiments of the British Indian Army.

Alec arrived in London in 1934, but left Dorothy and their baby son and returned to Gladys, his first and still-legitimate wife and his family, who now lived in Southampton.

In 1941 Alec finally left Dorothy, departing in uniform on a train after kissing his son Michael goodbye for the last time.

[7] In one of the 1943 documents, MI5's Director General, Brigadier Sir David Petrie, states that the fact Wilson was no longer in the service was "...perhaps some small compensation for the amount of trouble to which his inventive mind has put us all.

[34] Then-Chief of the Secret Intelligence Service, Sir Stewart Menzies, wrote: "I do not think it at all likely that we shall again have the bad luck to strike a man who combines a blameless record, first-rate linguistic abilities, remarkable gifts as a writer of fiction, and no sense of responsibility in using them!".

[31] Crook proposes that the British government took steps to prevent Wilson from "obtaining any kind of official or responsible employment" ever again, ending his publishing career and plunging him and his families into poverty.

He said his subsequent misadventures, including being declared bankrupt, though never discharged, and being jailed for petty theft, were part of the cover he had to adopt for operational reasons.

His tombstone notes that he was "also known as Alexander Douglas Gordon Chesney Wilson", describes him as an "author and patriot", and quotes Shakespeare's Othello: "He loved not wisely but too well".

[37][7] Wilson never divorced any of his wives, "instead keeping the women ignorant of each other's existence as he juggled his many separate lives and parallel families.

[9] Alison Wilson wrote a two-part memoir in an attempt to make sense of her husband's deceptions, lamenting that "he had not only died, he had evaporated into nothing.

[9] Crook concludes that Wilson's spy novels reveal details of intelligence work so precise as to indicate first-hand experience.

And the lack of evidence about Wilson's life may be due to an intelligence operation meant to expunge all traces of him from public records, Crook told a reporter.

[9] Actress Ruth Wilson, daughter of Nigel, is one of Alec's grandchildren,[39] and discovered that the children of Mike Shannon were also professionals working in playwriting, filmmaking and drama education.