It is always hard when one’s worst suspicions are confirmed. I had wanted Emily Mortimer’s new BBC adaptation of Nancy Mitford’s The Pursuit of Love to be excellent, and hoped that the dire trailer and inelegant promotional copywriting were not signs of things to come. Yet, unfortunately, they were portents of one of the worst opening episodes of anything that I have ever seen. Last Sunday, I sat slack jawed with amazement and disappointment as Mortimer and her excellent cast systematically dismantled one of the funniest, most poignant novels ever written. I had more laughs at my grandmother’s funeral.

Its central problem was that Mortimer, herself an actress of great intelligence and distinction, appeared to have no confidence in the material. Unlike the more traditional 2002 adaptation of the book, which conflated it with its sequel Love In A Cold Climate, the emphasis was on a frenetic directorial style that was equally indebted to Wes Anderson, Baz Luhrmann and Sofia Coppola’s Marie Antoinette. Heavy on the freeze frames, anachronistic rock music and voiceover, it attempted to be distinctive and unusual, but ended up surprisingly dull and derivative.

The Pursuit of Love will join the annals of the most disappointing things broadcast on the BBC in the past decade

What this did was to kill the book’s humour stone dead. The most egregious example of this was Mitford’s character Uncle Matthew, a fictionalised version of her “fa”, David Freeman-Mitford. In the TV adaptation, he is an off-the-peg eccentric bully, much given to ranting about “abroad” and foreigners. But in the book he is a far richer and funnier character, who at one point is driven to tears after seeing Romeo and Juliet. He announces that it is “all the fault of that damned padre … that fella, what’s his name, Romeo, might have known a blasted papist would mess up the whole thing. Silly old fool of a nurse, too, I bet she was an R.C. Dismal old bitch.” This does not make it into Mortimer’s retelling.

In fairness, I should note that the adaptation improves somewhat as it goes along, ditching the most egregious “look at me” flourishes. It offers a more conventional, rather staid retelling of the story, with heavy emphasis on Lily James’s Linda Radlett. But compared to Deborah Moggach’s earlier version, which managed to be both hilarious and poignant, it feels both redundant and strangely tame. All of the New Order and John Cale songs in the world cannot compensate for its hollow core, and devastating lack of emotional engagement. It will join the annals of the most disappointing things broadcast on the BBC in the past decade, or even fortnight.

The near-total failure of The Pursuit of Love is especially irritating because there have been several excellent examples of classic books being adapted sensitively and authoritatively over the past few years. These include James Wood’s sublime version of Waugh’s Decline and Fall, which manages the difficult feat of uniting the novel’s farcical humour and philosophical trappings, and Steven Pemberton’s hugely underrated Mapp and Lucia, which gave the great Anna Chancellor perhaps her most iconic role as Mrs Emmeline “Lucia” Lucas, a widow who arrives in the small town of Tilling and immediately causes social chaos. What both Pemberton and Wood understood was that the books needed to be made relevant to a 21st-century audience without sacrificing the humour and charm that had made readers warm to them over the past century, and both series were almost indecently entertaining as a result.

Both remained faithful adaptations, but there is much to be gained by a new spin on a well-known book, too. Sarah Phelps has established herself as the doyenne of Agatha Christie dramas after a spectacularly bold and dramatic 2015 version of And Then There Were None, which placed swearing, drug-taking and bloody violence within the Christie canon to memorable effect. And it was arguably equalled, if not bettered, by her 2018 adaptation of the Poirot novel The ABC Murders, which starred John Malkovich as the Belgian detective and managed to inject a heavy dose of Patrick Hamilton-esque bedsit realism into the whodunnit format. Both shows felt fresh and exciting, indicating that it is possible to take risks if the writing and direction and sufficiently confident, and that these can pay off spectacularly.

A poor, or even competent, adaptation will soon be forgotten

For many years, the stock BBC One Sunday evening costume drama has been reasonably formulaic in its ambitions. It would often revolve around the adaptation of a 19th-century classic, including but not limited to Jane Austen, Charles Dickens and George Eliot. The writer would, more often than not, be Andrew Davies, who has worked on everything from Middlemarch and Pride and Prejudice to Doctor Zhivago and Les Misérables. Only last year, eyebrows were raised when he was chosen to adapt Vikram Seth’s A Suitable Boy, rather than a writer of Indian origin. Yet the reason why Davies has had so much work over the past few decades is simple: he is an excellent writer who has all but defined what we expect of a mainstream literary adaptation, and remains the go-to British screenwriter for a television series based on a classic or contemporary book.

However, Davies cannot go on forever, and then it will be interesting to see what occurs. The acclaim and popularity of the recent adaptation of Sally Rooney’s Normal People, co-written by Rooney herself, suggests that broadcasters may well commission more contemporary drama based on bestselling novels with a large and appreciative audience who are only too happy to watch the filmed version of the book that they enjoyed a couple of years before. Sometimes, of course, this can backfire. Louis de Bernières’ Captain Corelli’s Mandolin was one of the major critical and commercial hits of the late Nineties, until a lacklustre 2001 film adaptation, complete with spectacularly miscast Nicolas Cage in the lead, derailed the bandwagon. No subsequent de Bernières novel has enjoyed anything like the same success.

Of course, even if the versions of much-loved books are disappointing, it is important to remember one salient fact, which is often forgotten in a rush to criticise a new adaptation. No matter how dire a television series, or film, it is ultimately unlikely to be remembered. But the books on which they are based will be around for decades, in some cases centuries. A poor, or even competent, adaptation will soon be forgotten. The novels on which they are based will endure, like a thing of beauty, forever.