Although he achieved national fame as the Machiavellian Francis Urquhart in BBC television's House of Cards (1990), Ian Richardson, who has died in his sleep at the age of 72, was primarily a superb classical actor. In his golden years at the Royal Shakespeare Company from 1960 to 1975, he played a long line of leading roles from Richard II to Richard III. Television and film later brought Richardson wider renown. But it was the clarion call of his voice and his capacity for glacial irony that, on stage, allowed him to shake hands with greatness.
Richardson was born in Edinburgh, educated at the city's Tynecastle school and trained for the stage at Glasgow's College of Dramatic Art. His Scottishness remained important to him and I recall him proudly telling me, when he played Sherlock Holmes on screen, how Conan Doyle partly based the character on a famous Edinburgh physician. But, after drama school, Richardson quickly joined the Birmingham Rep, then in its postwar heyday under Sir Barry Jackson.
With lightning speed, Richardson, at the age of 24, found himself playing Hamlet. The critic JC Trewin, who became one of the actor's fervent champions, found Richardson's youth was a palpable asset and, describing how he entered as "a slight, sad-eyed figure of settled melancholy", said his performance "grasped the imagination". Two seasons at Birmingham were followed by a swift transfer in 1960 to neighbouring Stratford where Peter Hall was building the RSC, of which Richardson became a vital component.
Richardson, who had a voice that could cut like acid, made an instant mark. I recall, even now, his first Stratford appearance in the seemingly thankless role of Aragon in The Merchant of Venice (1960). Speaking with almost finicky over-articulation and accompanied everywhere by his mother, he seemed a hilariously unlikely suitor for Portia. But he rose rapidly through the ranks to play Oberon in Peter Hall's 1962 Midsummer Night's Dream, the Antipholus of Ephesus in Clifford Williams's classic bare-boards Comedy of Errors in the same year, and Edmund in the international tour of Peter Brook's King Lear (1964).
But, interviewing Richardson in his Aldwych dressing room in 1964 when he was playing the Herald in Brook's The Marat/Sade, I was aware of his impatience to aim higher. He made some mildly undiplomatic remarks about feeling like an overlooked item in the RSC's stamp album, which he later rung me apologetically to withdraw.
His chance, however, was soon to come. In 1969 he was a Vendice of swirling evil in Trevor Nunn's black-and-silver rediscovery of The Revenger's Tragedy, and he followed this with fine performances as Cassius, Angelo, Prospero and as Ford in The Merry Wives of Windsor.
If any single production staked his claim to greatness, however, it was John Barton's 1973 Richard II in which Richardson and Richard Pasco alternated the roles of the king and Bolingbroke. Christopher Ricks, on the BBC radio programme, The Critics, vividly described Richardson's Richard as "like Charles I in the first half and Jesus Christ in the second". For my part, I recall his mixture of infinite sweetness, bruising irony and thunderous scorn. And Barton's radical notion of Richard and the usurper as mirror-images of each other paid off brilliantly with the transition of Richardson's Bolingbroke from apparently innocent victim to guilt-haunted wreck. Richardson and Pasco between them redefined the play.
Other fine performances followed. In 1975 Richardson lent his astonishing verbal bravura, seeming to take long speeches on a single breath, to Berowne in Love's Labour's Lost. In the same year he was a dazzling Richard III in Stratford's newly-opened The Other Place. Despite a cramping, high-concept production set in a psychiatric ward, Richardson gave us a Richard resembling a monstrous child whose ravening will had yet to be curbed by social custom. But there was also a sardonic, cold-eyed strength in his performance that he later turned to great advantage in House of Cards.
After leaving the RSC, Richardson became a somewhat nomadic figure, turning up on Broadway as Higgins in My Fair Lady and Humbert Humbert in an ill-fated Lolita. And, from the late 1970s onwards, he carved out a seductive and prosperous career in TV and film. But he was back on stage last year, first as a misogynist millionaire in Pauline Macaulay's The Creeper and then, more happily, as Sir Epicure Mammon in The Alchemist at the National. Listening to the voluptuous precision with which he articulated his dream of feasting "on the swelling, unctuous paps of a fat, pregnant sow", it was good to be reminded of the matchless clarity of the Richardson voice which remains one of the great treasures of my theatre-going lifetime.
He is survived by his wife, Maroussia Frank, whom he married in 1961, and their sons, Jeremy and Miles.
Philip Purser writes: In television, Ian Richardson excelled in bringing unsympathetic characters to life. As the politician who hovered balefully over the serial House of Cards he imbued the phrase, "you may say that, but I cannot possibly comment" with a Machiavellian menace. Much earlier, he was the mole finally unmasked by Sir Alec Guinness and slain by Ian Bannen in John Le Carré's Tinker, Tailor, Soldier, Spy (1979). And he was the newly arrived, spoilsport head of a high-living Cambridge college who nevertheless earned his Porterhouse Blue (that is, a fatal stroke) in Tom Sharpe's black comedy of that title in 1987.
Helpful and charming off camera, he could apply himself to more endearing roles. In Jack Pulman's Private Schulz (1981), he was the less than efficient mastermind of a Nazi plot to undermine Britain's wartime economy by flooding the country with fake £5 notes. The following year he scored a comic success as an old-fashioned, gentlemanly detective-inspector in Tony Bicat's spoof of the traditional country-house murder story, A Cotswold Death.
One of the challenges that came a TV actor's way in the 1970s and 1980s, with the vogue for historical drama-documentaries, was to impersonate famous figures. The secret was to imagine your way into the character and trust that this would capture his or her nature. Richardson took on Faraday, the discoverer of electricity, for the science programme Horizon, and Ramsay MacDonald for Number Ten (1982) - a series of potted histories of prime ministers. In the six-part Mountbatten, the Last Viceroy (1984), he made Nehru the most mercurial character in the story, admittedly not difficult when up against Nicol Williamson's wooden Mountbatten.
The one disappointment was his General Montgomery, in the 1979 Jack Le Vien co-production written by Ian Curteis, Churchill and the Generals. He gave the warrior an interesting, boyish undertone but when he repeated the role in the all-American Ike the same year, the impersonation was reduced to caricature.
Other hazards of working on television which Richardson faced were the snobbery which still regarded TV as the poor relation of theatre and cinema. In 1989 he was cast in a role that might have seemed tailor-made for a chilly exterior concealing a bold and generous heart - the eminent counsel who agrees, against all the odds, to represent the disgraced naval cadet in Terence Rattigan's The Winslow Boy. This was a brilliant television film production by Rattigan's biographer, Michael Darlow. Richardson was masterful. Alas, Rattigan had yet to be rehabilitated, and the version everyone now remembers is David Mamet's big-screen production 10 years later.
Richardson's last years saw him in Miss Marple (2004), as the Lord Chancellor in the BBC's Bleak House (2005), and last year, as the voice of Death in Terry Pratchett's Hogfather.
· Ian William Richardson, actor, born April 7 1934; died February 9 2007