There’s a socking great disclaimer at the front of my novels.

“This is a work of fiction. All characters and events in this work, other than those clearly in the public domain, are entirely fictitious. Any resemblance to any persons, living or dead, is purely coincidental.”

The real bits should be obvious. All you have to do is check out Marylebone, or amble down Hampstead High Street.

I’ve made up almost all the rest. Not that readers believe authors’ protestations.

Friends and family are apt to dissect published novels with an eye on ‘real life’. Even Ian Fleming, I’m told, suffered from this problem. People don’t just ask “Am I in it?” They go straight for “Which character am I?” I have half a dozen friends who believe they’re the single mother from One Night at the Jacaranda, and one who still thinks she’s the femme fatale.

“I’m Geoff,” insists my husband Jeremy. He has no discernible similarities with the doctor in my novels, though someone did once call him Geoffrey by mistake at a party.

Of course authors draw on reality when inventing their stories. Jane Davis says her favourite description of fiction is ‘made-up truth’. Her next book My Counterfeit Self was inspired by the plight of UK atomic war veterans. She even mentions many of them by name, but her book is still made up, and all the better for it, in my opinion.

Finnish author Helena Halme also uses the truth as a springboard for fiction. Her romantic series The Englishman is based on her own life story of meeting her Navy husband and moving to the UK. The prequel The Finnish Girl is now out, but, like the others in the series, reality has been fictionalized to provide the right pace and tension for a novel.

Fiction certainly benefits from an injection of fact. That’s what makes it relatable. I lost all faith in a story where the NHS doctor ‘worked shifts’. In those days, hospital doctors often worked a one-in-two rota. Going to work on Friday morning and not leaving till Monday evening was called many things, but a ‘shift’ it was not.

(I can’t help thinking a lot of non-fiction could do with a few facts too. Books on curing cancer with carrots really should move to the fantasy shelves, but that’s another story.)

A novelist invents stuff, but it needs to be right. While I can’t define ‘right’, I had to make that call with the image on the front of my forthcoming novel Hampstead Fever.  Cover designer Jessica Bell suggested adding a little red boat to the pond. The flash of red on the water seemed a delightful counterpoint to the red hat and red lipstick. But the pond in question is Hampstead Heath’s Number One Pond. Luckily one my sons, a local councillor, knows all about Hampstead’s ponds. As he explained, only the Model Boating Pond is a model boating pond. Cute as it was, my little boat had to be hauled out of the water.

Being right is more about authenticity than fact. Being authentic, or so the Oxford dictionary puts it, includes

“Made or done in the traditional or original way, or in a way that faithfully resembles an original.”

Ain’t that the truth?