[2] Melvin left his north London secondary school at the age of fourteen unable to master fractions but as head prefect, a qualification he said he gained by always having clean fingernails and well-combed hair.

Melvin attended evening classes at the nearby City Literary Institute and studied drama, mime and classical ballet.

In October 1957, he became an assistant stage manager, theatre painter and general dogsbody to John Bury, the set designer, and he was cast in his first professional role as the Queen's Messenger in the then in rehearsal production of Macbeth.

From the Scottish Court to a building site, his next performance was as a bricklayer in You Won't Always Be On Top, soon followed by a peasant in And the Wind Blew, Bellie in Pirandello's Man Beast and Virtue, Calisto in De Rojas's Celestina; Young Jodi Maynard in Paul Green's Unto Such Glory (all 1957) and then came the last play of the 1957–58 season, which was to be the start of an extraordinary year in the history of Theatre Workshop and Melvin's career.

[3] Both scripts had been transformed in rehearsals by Joan Littlewood's painstaking and inspired methods of getting to the truth of the text and building a lively poetic and dangerous theatrical event.

[5] In April 1960, William Saroyan, on a world tour, stopped off in London where he wrote and directed a play for Theatre Workshop in which he cast Melvin as the leading character called Sam, the Highest Jumper of Them All.

Rehearsals then started for Stephen Lewis's Sparrows Can't Sing in which Melvin played the role of Knocker Jugg.

Between the end of its London run and the opening at the Broadhurst Theatre in New York, the company visited the Edinburgh Festival with Shakespeare's Henry IV, Parts 1 and 2, in which Melvin metamorphosed as Gadshill, Shallow, Vernon and the Earl of March.

Defiant (1962), alongside Dirk Bogarde, and in Alfie (1966), where he played Michael Caine's work friend, stealing petrol and taking photographs to sell to tourists.

Alongside Melvin, who played the errant son, Lupin, were other actors from Littlewood's Theatre Workshop, including Bryan Pringle and Brian Murphy, who also became Russell regulars.

After the film, Melvin directed two works by The Devils composer, Peter Maxwell Davies: the theatre piece Miss Donnithorne's Maggot and the opera The Martyrdom of St Magnus.

He also appeared in The Adventures of Don Quixote (1973) as the Barber in the BBC television film directed by Alvin Rakoff and starring Rex Harrison.

In 1994, Melvin supplied the voice of the villain Lucius on the British children's animated TV series Oscar's Orchestra for the BBC and France 3.

In 2007 he appeared as the sinister Bilis Manger in the Doctor Who spinoff Torchwood, a role he then reprised for Big Finish Productions from 2017 on.

In July 2011 Melvin played the Professor in a short comedy/drama called The Grey Mile, a story about two ex-master criminals who are now confined to a care home.

It is partly in this role that he was becoming widely known as a learned and popular theatre and film historian — he can be seen and heard, for example, on the BFI DVD release of the Bill Douglas Trilogy.

These include four plays on LPs produced by Caedmon Records (Two Gentlemen of Verona (1965); A Midsummer Night's Dream; George Bernard Shaw's Saint Joan (1966); and The Poetry of Kipling).

[12][13] Without any living close relatives at the time of his death, he had former Stratford East director Kerry Kyriacos Michael appointed as his next of kin.