Sir Kingsley Amis was placed under MI5 "observation" while in the Army at the end of the Second World War because of concerns over his left-wing political views, newly-released documents have revealed.
The prolific writer was the subject of Security Service suspicion just days after VE Day while a lieutenant in the Royal Corps of Signals, his declassified file revealed on Tuesday.
The Lucky Jim writer and father of novelist Martin Amis was already known by MI5 to have joined the Communist Party as an Oxford student and had been logged as a "recipient of Communist literature" after being called up, documents released by the National Archive show.
There was a flurry of notes and letters about him after the war ended at a time when the intelligence services were shifting their focus away from defeated Nazi Germany and towards their former Soviet Union allies.
A memo regarding Amis, dated May 13 1945, five days after VE Day, reported: "This officer came to notice in 1942 (as) a student at Oxford University when he was reported to be a very promising member of the Oxford Branch of the Communist Party.
"Since being in the Army and in BLA (British Liberation Army) he is known to have been in touch with the Headquarters of (Communist party newspaper) the Daily Worker and it is therefore reasonable to suppose that his political views have not changed in any way."
The letter suggested getting a report from Amis's commanding officer (CO) about him and in a memo to MI5's Lt Col John Baskervyle-Glegg, the unnamed CO said he had not found the socialist young officer to have a "particularly inspiring personality".
He added: "He is obviously well-read but a bit young and inexperienced in the ways of the world.
"In discussions he has always tended to take extremist views towards most aspects of life and gives the impression of trying to compensate for his rather nebulous personality by making extreme and controversial statements in the hope it will make an impression."
He added that Amis's immediate company commander did not report him showing "extremist tendencies" in his work, adding: "My own view is that if he tried to, there are few people who would take him seriously."
However, a subsequent letter from Baskervyle-Glegg on July 4 that year noted: "I am interested in what the CO (commanding officer) has to say about this officer, particularly as it tends to confirm what we already knew about him.
"There seems to be little doubt that his left-wing opinions have not changed to any extent since he first came to notice and I accordingly think that he should remain under observation for the time being."
The file notes that Amis was demobilised from the Army the following October.
After the war, he returned to Oxford and was very politically active, never hiding the fact that he was a socialist.
His file shows that his MI5 file and vetting led to him losing a position on a lecture tour in 1955, organised by the German Information department at the Foreign Office.
But it also catalogued how his politics softened in the 1950s, particularly after the 1956 Soviet invasion of Hungary.
In February 1957 he wrote in the Daily Worker, later renamed the Morning Star, that he had "utterly rejected" Marxism.
Sir Kingsley was knighted in 1990 and died in 1995 at the age of 73.