There aren’t many absolutes I use to decide whether or not I like a person. I’m vegetarian, for example, but I don’t mind at all that my friends aren’t. I’m happy to disagree with people politically. And I don’t even care if they like team sports, when I only watch tennis, boxing and darts. But one of my deal-breakers, one of the few things I can’t negotiate if we are to be friends, is that you must fully and entirely believe that Joan Hickson was the best of all Miss Marples.

It’s ok if you’ve never read or watched a Marple, obviously – you’re allowed not to have an opinion on Marple at all, and we could still get on just fine. But if you genuinely believe that Geraldine McEwan or June Whitfield is a better Jane Marple than Joan Hickson, we will never swap numbers and drink mojitos together, for the simple and excellent reason that you are an idiot.

Miss Marple is most perfectly described by Jason Rafiel (played by Donald Pleasence) in the BBC adaptation of A Caribbean Mystery, as ‘a little old lady who knits and wears lace. She also has a mind like a bacon slicer’. And that’s what Hickson captured in spades: English frailty and fluffiness with a ruthless iron core, like candyfloss wrapped round a kitchen knife. So Margaret Rutherford was too sturdy, Helen Hayes too American, Angela Lansbury too joyless.

And yet all of these women seemed like dream casting when Disney announced earlier this week that they were rebooting the Marple franchise with Jennifer Garner in the title role. That would be Jennifer Garner, action heroine and all-round youthful hottie. Not her gran, who might happen to have the same name.

Before we go any further, let me explain that I have no problem with Jennifer Garner. I like her in Juno, where she is easily the least annoying person in the cast. I like her in Alias, where she is a superspy with a boy’s name and lovely hair. I even like her in Elektra, an almost unwatchable pile of tosh where she plays a superhero warding off supernatural assassins with her fighting skills.

But none of this qualifies her to play Miss Marple for at least another thirty years. Miss Marple is old, and that is part of her character. She has earned her insight into human nature from being alive for ages. As Agatha Christie herself said, ‘There was no unkindness in Miss Marple, she just did not trust people. Though she expected the worst, she often accepted people kindly in spite of what they were’. That combination of low expectations and tolerance is something most of us have to grow into.

The author must be rotating in her grave at the very mention of Jennifer Garner in the same sentence as Jane Marple. Christie based Marple on friends of her grandmother and on her earlier character of Caroline Sheppard in The Murder of Roger Ackroyd. When Roger Ackroyd was adapted for the stage, Caroline’s character became much younger. So peeved was Christie that she created Miss Marple, so that the old maid couldn’t simply be removed from a story next time.

She presumably couldn’t foresee a world where a company could buy the rights to a character, and then completely disregard everything about that character which defines them. Because surely it would be easier to simply write a new detective character for Jennifer Garner: one who is in her thirties, and American, and good at fight sequences. Why bother using the brand name of Miss Marple if you’re not going to cast someone who fits it? People who know the Marple stories will think you’ve lost your mind and/or are evil, and people who don’t know them won’t care.

If Disney is so unsure of the audience for a new murder mystery starring Jennifer Garner, why not pick a literary character for her to play which fits her? She would, after all, make a perfect grown-up Nancy Drew.