When it was announced that the actor Paul Ritter had died, cruelly young at 54, of a brain tumour, social media was despondent. One of his best-known phrases from the comedy Fright Night Dinner in which he starred — “lovely bit of squirrel” — briefly trended in its own right. Tributes were paid by the show’s writer Robert Popper, who described Ritter as “a lovely, wonderful human being”, as well as “the greatest actor I ever worked with”, and many of his peers. Mark Gatiss said simply: “What an actor. What a presence”, and Rufus Sewell wrote that he was “one of the best, funniest and most natural actors I ever worked with”.

Ritter would have been sublime in all manner of classical parts

Ritter was a performer of extraordinary versatility and range, who became best known late in his career for two contrasting performances in Friday Night Dinner and Chernobyl. The first was a much-loved family sitcom, in which Ritter’s character Martin Goodman, the eccentric and frequently shirtless patriarch, not only stole the show most episodes — an impressive feat, given that his co-stars included Tamsin Greig, Simon Bird and the great Mark Heap — but managed to anchor the farcical goings-on with a sense of emotional truth. One never stopped believing in Martin’s decency or love for his family, even while he was pronouncing his exasperation with whatever absurd situation he was embroiled in with the words “Shit on it!”

And the much-acclaimed Chernobyl, a drama about the nuclear disaster, has attracted praise for the work of its fine ensemble cast including Jared Harris, Emily Watson and Stellan Skarsgard. Yet it was Ritter as Anatoly Dyatlov, Chernobyl’s deputy chief engineer who was subsequently blamed for the catastrophe, who was in some regards the most interesting character in the show. Nominally the antagonist, Ritter played Dyatlov with an understated and quiet bitterness but refused to turn him into a straightforward villain, instead conveying a powerful sense of the awfulness of bearing responsibility for one of the most notorious examples of mismanagement that ever took place.

His great skill as an actor was to look for the tragic in the comic, and vice versa

Ritter began his career in small roles in TV and on stage in the Nineties, but did not come to public prominence for many years; hardly an unusual state of affairs for fine character actors. He worked extensively at the National, appearing in plays such as All My Sons and The Coast of Utopia, and was nominated for an Olivier Award in 2006 for his performance in Coram Boy. He later appeared in The Curious Incident of the Dog in the Night-Time in 2012, which led the playwright Simon Stephens to say of him in tribute that” “[Ritter] inspired me always with his wit and intelligence and rigour. He was a writer’s dream.”

It is an enormous shame that the sole Shakespearean role that he took on screen was Pistol in the TV adaptation of Henry IV Part II in 2012, as Ritter would have been sublime in all manner of classical parts. While he would not have been obvious casting as Hamlet or Romeo, one can only imagine how interesting his Iago, his Cassius or his Malvolio might have been, and what unusual things he might have done. His great skill as an actor was to look for the tragic in the comic, and vice versa, and thereby create characters who were both multi-faceted and deeply, recognisably human.

There were some larger roles at the end of the Noughties, including small parts in Harry Potter and James Bond, but he was still playing characters with names like Mad Bob and Record Shop Owner. Yet his part in Friday Night Dinner brought him to far greater prominence in Britain, and he became near-ubiquitous for many years. I especially treasured his performances in Mapp and Lucia, in which he played the “Scottish” clergyman Rev Bartlett, and the bewildered Dave in Urban Myths, which wittily explored the apocryphal story about Bob Dylan arriving in Crouch End to see the musician Dave Stewart and accidentally meeting the wrong Dave. Ritter was perfectly cast as a bewildered but delighted everyman, confronted with his idol in his home, and the role showcased his innate ability at making the audience believe in his characters with great economy.

Ritter was one of those actors that was too versatile to be typecast

He was too versatile to be typecast, but if he had a best-known style of TV and film performance, it was the slightly untrustworthy authority figure. Whether he was playing a spymaster in The Game, the legal clerk Wemmick in Great Expectations or Sir John Seymour in Wolf Hall, there was something about Ritter that conveyed a sense of dignity, undercut with unease. Which is not to say that he didn’t excel at comedy, as Friday Night Dinner demonstrated so superbly, and which he also showed in a 2016 stage revival of Art, alongside Tim Key and Rufus Sewell. As Key wrote in a tribute to him, “It’s natural to want Paul Ritter in your dream cast. And you know he’ll be the best thing in it.”

There should have been decades more of great work, which now we shall never see, due to his far too premature death. What we have is the work of a great actor who seldom achieved top billing, but who assiduously and consistently stole the show from his better-known co-stars. Comparisons were made between him and the American actors John Cazale and Philip Seymour Hoffman, but the man I thought of as an analogy was Denholm Elliott, another committed scene-stealer who could turn the smallest parts into gold and whose presence in the credits guaranteed that, whatever the quality of the rest of the production, his performance would be a memorable one.

Ritter’s final appearance will be in the eagerly awaited film Operation Mincemeat, about the World War Two plot to divert attention from the Allied invasion of Sicily by using a decoy body. Ritter plays Bentley Purchase, the coroner who provided the body that was used. Only a fool would bet against him being as adept and brilliant in that as he always was in everything else, and it can only be hoped that it forms a fitting epitaph to a fine career.