Will lightning strike twice for Harry Potter and the spin-off film?

“I always knew that Harry's story would end with the seventh book... Deathly Hallows is my favourite, and that is the most wonderful way to finish the series,” JK Rowling said in 2007. Last year, she moved away from witchcraft and wizardry with an acclaimed and moderately successful crime novel addressing the ills of modern, Tory-led Broken Britain. She seemed to be bravely moving forward. And then came the inevitable announcement.

There will be a new Harry Potter film. It's not cashing in, she says. It's a legitimate and exciting spin-off, Warner Bros. try to argue. The film is based on the 2001 booklet ‘Fantastic Beasts and Where to Find Them’, a directory of mythical beasts originally written for Comic Relief.

To be fair to Rowling, she has remained almost true to her word. It's neither a prequel nor a sequel. In fact, it isn't really even a book. It's an A-Z list of made-up animals, recreating one of Harry's school textbooks on Magizoology.

According to Rowling, the film will focus on the life of little-known character Newt Scarmander, 70 years before Harry and his lot came along, presumably going around finding different beasts. And what wouldn't be thrilling about watching two hours of a magical Noah's Ark PowerPoint slideshow? Here is a Hippogriff. Oh, look, a Flobberworm. Look at the teeth on that Acromantula. And so on.

As a Potter fan, I have put aside my cynicism for all the books and the films. Yes, it’s making lots of money, but it also has well-drawn characters and sound moral lessons. But, even to me, this new project sounds like a lot of CGI-generated beasts with great potential for more related merchandising, video games, apps, theme parks and whatnot. So, yes, kind of milking the franchise.

Cast aside your Divination notebooks and put away those Potions recipes, Joanne. What have you learnt from history? Are sequels ever good? Or, how often do you see a genuinely great film that has a number or a colon in the title? You’ve already had seven – do you need any more?

This summer's film sequels/prequels/remakes/spin-offs are indicative of wider franchise trends. You may have been fooled by Before Midnight (the third instalment in one of film's perfect trilogies), Alan Partridge (a spin-off from the TV shows), and Ulrich Seidl's 'Paradise' trilogy, all of which have been worthy examples of franchises.  ‘Only God Forgives’ (a semi-follow-up to Drive), was divisive, but it sparked fierce debate among cinephiles and was hailed as a masterpiece by some. The occasional sequel in the past (Mad Max II, Toy Story II and III, Godfather II) has even been better than the first.

However, history is littered with ill-judged sequels (e.g. Godfather III, Star Wars I-III, Twilight, etc). We are all still trying to forget Indiana Jones and The Crystal Skull. And, true to form, most of this summer's franchise offerings (Kick Ass 2, Grown Ups 2, Smurfs 2, Monsters University and The Wolverine), were not so good. Iron Man 3 was received as kind of 'meh'. And it doesn’t end here: there is a Jurassic Park 4 film in the works, and even more Star Wars on the horizon.  

Step away, JK. The new film might be great. Odds say it probably won't be. Ok, your last book ‘The Casual Vacancy’ was flawed. ‘The Cuckoo’s Calling’, published under pseudonym Robert Galbraith, sold relatively well for an unknown author, even if it wasn’t a runaway success. But at least they weren't Potter. Look to David Bowie: he has re-invented himself every couple of years, sometimes successfully, sometimes less so (hello, Tin Machine), but he hasn’t just stuck with something that has been proven to work. Like Woody Allen says about relationships (or sharks, or artists): if it doesn't move forward, it dies.

If the aim is to raise money for Comic Relief, great. It wouldn’t necessarily make it great art, but it would be for a worthy cause. If the aim is to further fund the studios - and they've already squeezed two films out of the final book – don’t do it. They'll just spend the money on more sequels anyway.