It started out as dubious Twilight fan-fiction and quickly became a worldwide phenomenon – dubbed “mummy porn” for its somewhat socially-acceptable lasciviousness.

Now, the book that divided readers (half say it’s every fantasy they’ve ever had in one book, others say it’s a disgrace to literature) is headed for the silver screen.

The first cinematic trailer for E.L. James’ Fifty Shades of Grey movie adaptation has exploded onto the internet as quickly and as powerfully as its protagonist transitions from innocent college student to all-out sexpot.

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For those who are new to this, the film documents the relationship between the meek Anastasia Steele and her older boss, Mr Grey, a mysterious, brooding multi-millionaire with model good looks and a penchant for sadomasochism.

Critics have been quick to lambast the preview, with The Telegraph deeming it “about as arousing as week-old meat loaf”.

However, for Fifty Shades virgins, the trailer may come as a welcome surprise. Read: it’s actually not that bad.

Here’s why:

The cast

One of the movie’s greatest assets appears to be its actors. When casting Anastasia Steele, names like Emma Watson and Bella Heathcote were bandied around – young, wide-eyed ingenues for whom the dark, erotic bedroom adventures would be about as believable as Donald Trump’s hair.

To the credit of the filmmakers, they’ve shirked the suggestions and gone for Dakota Johnson, daughter of Melanie Griffith.

From the trailer, it’s clear they’ve made the right choice. Johnson is appropriately plain, but with a dark side that makes her inevitable transformation to minx believable.

Meanwhile, the brooding Mr Grey character is played by Irish model Jamie Dornan – an accidental casting of sorts.

The original choice was rugged Sons of Anarchy star Charlie Hunnam, but rumours are he quickly baulked at the content of the movie and bailed, although he cited family reasons.

Dornan is a welcome addition; not strikingly good looking, but appropriately cold and intimidating.

The soundtrack

At the risk of joining the Beyonce worshippers, her exclusive redo of “Crazy in Love” sounds pretty spectacular against the backdrop of artistic shots of whips and chains. She’s managed to make an early 2000s hip-hop hit sound cinematic.

If the rest of the soundtrack is in a similar vein, it may not matter what’s happening on the screen.

The look

Alright, so it’s effectively a jazzed-up soft porno, but at least it’s done well. The dark, moody lighting and gleaming set seem perfectly suited to the elusive Mr Grey and the sex scenes appear to teeter gracefully on the brink of tacky.

And so it should: cinematographer Seamus McGarvey has some pretty solid credentials, having also worked on Atonement and The Hours.

Plus, it’s worth mentioning that Mr Grey’s suits appear perfectly cut – very important for characterisation.

The content

All four Twilight films trumped the box office and made hysterical screaming fans the norm. Imagine what a sexed-up version of that could do.

While movie-goers may be slightly embarrassed to see the movie at cinemas, we predict DVD sales will be through the roof.

With attractive people, helicopters, bachelor pads and the infamous “red room”, there’s no way this movie won’t find an audience.