Until the Evening News folded in 1980, Barker was one of the busiest stage and film critics of his generation, phoning in his theatre notices between press shows and still "catching" up on any stately home that happened in his path.
Even before the Second World War, when Barker was the Evening News's deputy reviewer on films and plays, the ninth Earl of Bessborough, himself a theatre addict, would fondly recall the breezy arrival one day at Stansted Park, Bessborough's historic pile in Hampshire, of young Barker at the wheel of an open-top car with Charles Morgan, the novelist and playwright, then chief drama critic to the Times, a wind-blown companion.
Barker never missed such architectural or historical opportunities or the chance to improve his own place when it came into his possession. Almost alone he excavated part of the lawn at Watermill House to create a small lake with an island for his large circle of friends to enjoy at Christmas.
No one paid greater heed to the advice of Polonius about friendship. Barker kept scores of friendships going from boyhood, partly through the agency of an elaborate Christmas card.
At the outbreak of war he had joined the 51st Highland Division (the Gordon Highlanders), engineering a transfer as soon as possible to the Balmorals, the regiment's concert party run by Capt Stephen Mitchell, the London theatre manager, with Ian Carmichael and Bunny Playfair. When Barker, who joined the Army as a private and left as a sergeant, went to France with the Balmorals on D-Day plus six, he turned his hand to making costumes for the male cancan dancers, using discarded parachutes.
Back at the Evening News in 1946 he was a journalist in an age when his paper encouraged him to travel. He went to Greece and the Middle East to experience for his million readers the seven wonders of the world. He went to South America in search of El Dorado; and he went to films by day and plays by night as deputy to Stephen Williams (theatre), whom he succeeded in 1958, and Jympson Harman (films), whom he succeeded in 1960.
While still reviewing for the Evening News, Barker broadcast a weekly programme on the theatre for LBC in 1977 and 1978.
His books ranged from The Oliviers, the first - and I think still the best - biography of Laurence Olivier and Vivien Leigh, to The Black Plaque Guide to London (1987), written with Denise Silvester-Carr and republished last year as Crime and Scandal - a guide to "the dens of iniquity and abodes of infamous people who have lived in London". Among them were "Agitators, Blasphemers, Deviants, Fanatics, Imposters, Malcontents, Necrophiliacs, Satanists, Sodomites, Traitors and Whoremasters".
As sometime president of the Critics' Circle and chairman of the film and theatre sections, Barker could be counted on to raise a head of steam for any cause from battles with the Censor or the managers or anyone trying to muffle what he saw as the rights of reviewers to review.
Every year or so this most genial of critics gave parties at Watermill House. He relished them and they left hundreds of departing guests feeling slightly grander than when they arrived.
Richard Felix Raine Barker, writer, theatre and film critic: born London 7 May 1917; married 1950 Anthea Porteous (nee Gotch; one son, and one daughter deceased); died 11 July 1997.