After a series of false starts, including a spell as a jobbing labourer and another as a clerk in a local government office, Sim's love of and talent for poetry reading won him several prizes and led to his appointment as a lecturer in elocution at the University of Edinburgh in 1925.

His films included Green for Danger (1946), Hue and Cry (1947), The Happiest Days of Your Life (1950), Scrooge (1951), The Belles of St. Trinian's (1954) and An Inspector Calls (1954).

[2] The family lived above his father's shop at 96-98, Lothian Road;[3] later, improved finances allowed for a move to 73, Viewforth, in the wealthier Bruntsfield area of the city.

[7] His announcement was so badly received that he left the parental home and spent about a year in the Scottish Highlands with a group of itinerant jobbing workers.

In his spare time, he joined poetry reading classes, winning the gold medal for verse speaking at the Edinburgh Music Festival.

After taking an advanced training course in his subject, in 1925 he successfully applied to the University of Edinburgh for the post of Fulton Lecturer in Elocution, which he held for five years.

[1][10] Sim followed Othello with productions ranging from a musical revue to a medieval costume drama by Clifford Bax, in whose The Venetian he made his Broadway debut in October 1931.

When he recovered, he made a strong impression on West End audiences as Ponsonby, a sycophantic bank director in the comedy Youth at the Helm.

[8] There followed a sequence of films, a mixture of comedies and detective stories, including Wedding Group (1936), in which Sim and his wife both appeared, he as a Scottish minister, she as the maid; Edgar Wallace's The Squeaker (1937), after a stage production of the same piece; Alf's Button Afloat (1938) with the Crazy Gang; also in 1938 he played a revengeful ex-con Soapy Marks in the Associated British Picture film The Terror, and the "Inspector Hornleigh" series (1939–41), as the bumbling assistant of Gordon Harker.

he played Professor Hayman, making him, as The Manchester Guardian put it, "baleful as a shaven John Knox and lean as a buzzard… a grand performance".

His other films included Waterloo Road (1944), London Belongs to Me (1948), Alfred Hitchcock's Stage Fright (1950), Scrooge (A Christmas Carol) (1951), Folly to Be Wise (1953) and An Inspector Calls (1954).

Having originally accepted the part of Clarence, Sim agreed to play in drag as Miss Fritton when Margaret Rutherford proved unavailable, and the director and co-producer, Frank Launder could find no suitable actress as an alternative.

[23] His "Burke and Hare" film The Anatomist debuted on British television (on "International Theatre") on 6 February 1956, and was later released theatrically in the U.S. in 1961, leading some reference sources to list it as a 1961 movie.

[30] The second was William Golding's The Brass Butterfly, a 1958 comedy described by The Times as portraying the relations between an urbane Roman emperor (Sim) and a Greek inventor with wildly anachronistic scientific ideas (George Cole).

His range was wide, from Prospero in The Tempest (1962) and Shylock in The Merchant of Venice (1964), to the villainous Captain Hook in Barrie's Peter Pan (1963, 1964 and 1968) and the hapless Mr Posket in Pinero's farce The Magistrate (1969).

The new plays in which Sim appeared were Michael Gilbert's Windfall (1963), William Trevor's The Elephant's Foot (1965) and Ronald Millar's Number Ten (1967); he directed all three productions.

The first was dismissed by The Times as a tepid comedy about a progressive young headmaster thwarted by a reactionary member of his staff; the second, billed as a pre-London tour, started and finished in the provinces; the last was castigated by Philip Hope-Wallace in The Guardian as "maladroit playmaking" with a tedious plot about political machinations.

[35] Sim's performances provided some consolation: in the first, The Times said, his "treacherously sweet smiles, triple takes and unheralded spasms of apoplectic fury almost make the evening worth while".

At least half a dozen others – 'our boys' as Naomi called them – mostly unhappy at home, have cherished memories of life at Forrigan, the welcoming woodland retreat built by the couple near Henley-on-Thames in 1947".

[1] An English Heritage blue plaque was unveiled in July 2008 at his former home at 8 Frognal Gardens, Hampstead, by his daughter Merlith McKendrick at a ceremony attended by George Cole.