Of all the classic generation of British and Irish actors who found they had a new lease of world-fame due to recurring roles in the Harry Potter movie franchise, perhaps the most iconic was Michael Gambon, who took over the role of the mysterious, snowy-haired Hogwarts headmaster Albus Dumbledore when Richard Harris died in 2002. It put him in charge of the school and at the head of the Hogwarts high table in Prisoner of Azkaban (2004), Goblet of Fire (2005), Order of the Phoenix (2007), Half-Blood Prince (2009) and Deathly Hallows Parts 1 and 2 (2010-11). It was an undemanding role perhaps, and Gambon’s delicate health and dislike of learning lines made it a very congenial one, but he brought to Dumbledore his own capacity for unworldliness and gentleness. Harry Potter made him a monarch-like figure whose rule extended to the imaginations of children the world over, and he had a genuinely unforgettable scene with Daniel Radcliffe in the second half of Deathly Hallows, when Voldemort casts the killing curse on Harry, who awakens in an eerie white limbo where he meets and talks with Dumbledore about matters of life and death. There was something awe-inspiring for both children and grownups about this vision of death and its nearness, and Gambon was an ideal guide. Over his career, the movies were probably not as important to Gambon as the stage or TV, and he tended to be cast in relatively small or cameo roles – although always with a disproportionate impact – starting with his low-key company role in the Olivier Othello in 1965. Despite the supernatural virtue and wisdom of Dumbledore in his later years, Gambon was often at home in bad-guy parts, perhaps most notably as the thief in Peter Greenaway’s The Cook, the Thief, His Wife & Her Lover from 1989. This character was the sinister and odious mobster Spica, married to Helen Mirren (and so paired in British moviegoers’ minds with Bob Hoskins, who had been Mirren’s gangster husband in The Long Good Friday). Gambon showed us someone authentically pugnacious and psychotically obnoxious, preening himself in the restaurant he owns and intuiting his wife’s affair with a shy bibliophile played by Alan Howard. Gambon gave that role a sulphuric cockney menace, but he also had a great line in dissolute or scapegrace aristocrats and plutocrats, and switched between rough and posh like a seasoned thespian. In Iain Softley’s The Wings of the Dove from 1997, he was the reprehensible Lionel Croy, whose daughter (played by Helena Bonham Carter) has to make hard financial choices after her father’s spendthrift ways. For Julian Jarrold’s Brideshead Revisited in 2008, he was a regal Lord Marchmain (the role that went to Olivier on TV). In Robert Altman’s country house murder mystery Gosford Park (2001), written by Julian Fellowes, he was superb as the intemperate, malign Sir William McCordle, to whom some awful fate is clearly heading – a bigger, nastier and more potent character than anyone in Fellowes’ TV series Downton Abbey. And Gambon upgraded easily to royalty, being of course acting royalty himself, in what may come to be seen as the most triumphant of his screen cameos: the gruff and cruel George V in Tom Hooper’s The King’s Speech, coolly demonstrating to his speech-impediment-affected son, the Duke of York (Colin Firth) how a consummate professional handles a radio broadcast, and then brutally humiliating the stammering duke, making him feel like a wretched guilty schoolboy. Gambon embodied the smugness and the emotional coldness and distance of the part. For Michael Mann’s big tobacco conspiracy thriller The Insider in 1999, Gambon was superb as the hatchet-faced corporate apparatchik Thomas Sandefur, whose mission is to stop the public discovering first, how lethal cigarettes are, and second, how lethal the cigarette business had long known them to be. I think my favourite Gambon screen performance is another bad-guy role, and what I think was his only western: Kevin Costner’s Open Range from 2003, in which he plays villainous Irish rancher Denton Baxter, who resents the cattlemen played by Costner and Robert Duvall from availing themselves of “open range” rights on his land. With venomous dislike and a broad accent, he denounces the “free gra-a-zers!” It’s a role which perhaps he imagined himself playing on stage, relishing every melodramatic flourish. Gambon always delivered more than expected and turned every supporting role and cameo into a star turn.