It is that special time of year, when England unites to complain about the historical inaccuracies in The Crown and then settles down to enjoy a television series everyone knows is fictionalized.

At the same time, the French press is in a lather over the depiction of Napoleon in Ridley Scott’s latest epic, complaining that the emperor did not take part in cavalry charges, did not fire a cannon at the pyramids and was not exactly the “sentimental brute” depicted. French audiences will love it.

The purists and pedants are outraged on both sides of the Channel. French historians furiously point out that Marie Antoinette had her hair cut short before being guillotined (and Napoleon did not witness the execution). British historians insist there is no evidence that Diana came back as a ghost in Charles’s private jet.

Napoleon, directed by Ridley Scott. Did the French emperor really shoot off the Great Sphinx’s nose?

Fact-based historical film and television drama has never been more popular and the accusations of inaccuracy have never been fiercer. But, at the same time, filmmakers feel an obligation to historical precision that seldom troubled them in the past: films cleave closer to verifiable history than ever before.

The purists and pedants are outraged on both sides of the Channel.

Three of my books became films or TV series last year, and many people demanded that I should be furious about the SAS going to war with a soundtrack by AC/DC, or about the Black character introduced into the Philby story, or the love interest in the film of Operation Mincemeat. One journalist even detected a sinister, gender-political plot in the adaptations, since all three scripts included women who had been partly or wholly invented.

Kelly Macdonald and Matthew Macfadyen in Operation Mincemeat, a film adaptation of Ben Macintyre’s book.

Far from being unhappy with these reinterpretations, I was delighted. In each case, the screenwriter took the true story and remade it in a new art form, for a different audience, with close historical guidance. Each was faithful to the essence of the tale, context and period detail.

Films and television dramas are not documentaries, scholarly histories or journalism. Filmmakers are not trying to reflect truth (which is impossible anyway) but rather to create a new, believable emotional reality. These are screen novels, taking the past as a guiding framework and creating imagined drama from it. Complaining that this is not an exact replication of the past misunderstands the genre. As our own film critic pointed out, Scott’s Napoleon is “not a painstakingly accurate history lesson but an impressionistic portrait”.

Filmmakers use various locutions to cover themselves against historical counterattack: “Based on a true story” or “Inspired by real events”. The screenwriter Steven Knight came up with a brilliant, tongue-in-cheek half-disclaimer for SAS Rogue Heroes: “Those events depicted which seem most unbelievable … are mostly true.”

McQueen, Jud Taylor, and James Garner celebrate the Fourth of July in The Great Escape.

In the past, dramatists seldom let facts get in the way of the story. The Great Escape (1963), for example, opens with the unequivocal statement: “This is a true story.” In the most memorable scene, Steve McQueen, playing the American air force captain Virgil Hilts, leaps the barbed wire on a motorbike. This did not happen. There were no Americans in Stalag Luft III at the time of the escape, and the motorcycle ridden by the “Cooler King” was not built until 1963. The three successful escapers are depicted as British, Australian and Polish. They were Norwegian.

Mel Gibson’s Braveheart (1995) remains a terrific film, even though William Wallace never wore woad, or a kilt, let alone that ridiculous mullet. He was not even “Braveheart”; that was Robert the Bruce (probably).

Pearl Harbor, the 2001 epic starring Ben Affleck, contained no fewer than 118 historical inaccuracies, including Japanese Zero fighters painted the wrong color to make it easier for viewers to identify enemy planes.

Ringo Starr in Lisztomania, a surreal biographical musical comedy about the flamboyant 19th-century composer Franz Liszt, 1975.

The least accurate “historical” film of all time may be Ken Russell’s surreal Lisztomania (1975), which features Roger Daltrey as the 19th-century Hungarian composer, Ringo Starr as the Pope, Rick Wakeman as Thor and ends with a spaceship attack by a zombie Richard Wagner (Paul Nicholas) dressed as Hitler.

Mel Gibson’s Braveheart remains a terrific film, even though William Wallace never wore woad, or a kilt, let alone that ridiculous mullet.

Some films have deliberately distorted the past to make a political point, in a way that seldom happens today. Oliver Stone’s JFK (1991) is a conspiracy theory dressed up as history pretending to be a documentary: much of it is simply false.

Sophisticated modern audiences expect historical films to bear a credible resemblance to the past. They can spot the difference between artistic license and outright falsification, an inaccuracy that matters (who shot JFK), and one that does not (the length of Marie Antoinette’s hair). Before Season Five, The Crown agreed to label itself “fictional dramatization”, as if anyone really imagined it was anything else.

Oliver Stone’s JFK, starring Kevin Costner (pictured), Gary Oldman, and Donald Sutherland, 1991.

Fusspots fear that film history will elbow out real history, that naïve viewers will somehow end up genuinely believing that the ghost of Diana haunted the future king. The case usually cited is Richard III, whose unkind portrayal by Shakespeare as an evil hunchback saddled the king for more than three centuries.

The reverse is truer. Millions watched Stone’s JFK but surveys showed that only 1 percent changed their minds about the assassination: sensible filmgoers did not believe the conspiracy theory before watching, and they did not believe it afterwards.

Even partly inaccurate film history inspires hunger for the real thing. The Imitation Game, starring Benedict Cumberbatch, played fast and loose with the Enigma story but led to a massive surge of interest in what really happened at Bletchley Park.

Inexplicably, historical films and historical fiction are held to very different standards. The late Hilary Mantel’s novels, for example, depict genuine characters in a specific historical context, creating new dramatic narratives out of them. Each new volume in the “Wolf Hall” trilogy was greeted with rapture, not a dreary raking of the text in search of historical errors.

Historical films should be treated in the same way as historical novels: as entertainment, performance, new colors painted on top of an old canvas, in which the most unbelievable elements are mostly true.

Ben Macintyre is a writer at large at The Times of London and the best-selling author of The Spy and the Traitor, A Spy Among Friends, Double Cross, Operation Mincemeat, Agent Zigzag, and Rogue Heroes, among other books