Invasion Planet Earth (UK 2019: Dir Simon Cox)

Imagine. You're a filmmaker, maybe not in the first flush of youth. You've had one not very well publicised feature made years ago, but you have a project within you so ambitious in scope that it becomes an all consuming passion. But you have little resources, financially or technically, at your disposal, to realise the vision. So what do you do?

If you're Simon Cox, you crowdfund, you find some willing investors, and you learn how to achieve the effects you want onscreen yourself. And you exercise patience. A lot of patience. But boy was it worth it.

In the movie's 1980s prologue, a young boy, Tom, is glued to a TV show called 'Kaleidoscope Man' (the original title of the film, dropped when the director thought it might be too confusing). He dreams of being a superhero and saving the world - hold that thought.

Flash forward to now; Tom is all grown up (Simon Haycock) and things aren't going so well for him. He's still getting over his father's death, and Tom and his wife Mandy (Lucy Drive) also recently lost a child. Their heartbreak is slightly relieved when Mandy, a teacher, tells Tom that she's pregnant. "This is our new start," she tells him optimistically. So you know things aren't going to go well.

Later that day Tom, Mandy and various others in the town, including the local priest, are subject to the same weird hallucination; of apocalyptic scenes, explosions and burning cities. The vision is over as quickly as it began, but leaves all the witnesses shocked. At school Mandy tells the children the story of Noah and the ark. Tom is a doctor who works at a care home, managed by Claire Dove (Toyah Willcox, who gets to sing the end theme song too), which provides support for people with a range of mental health problems, and which is facing closure by the Council. Among the patients are Harriet, an angry woman with a narcissistic personality disorder (Julie Hoult), Floyd, a paranoid schizophrenic (Danny Steele) and manic depressive artist Samantha (Sophie Anderson) whose wild paintings include a representation of a mushroom cloud, part of the same hallucination experienced by Tom and the others.

The aliens strike in Simon Cox's Invasion Planet Earth

As if the hallucination was an early warning, it's not long before the real invasion comes to town. Amid the 'War of the Worlds' style devastation (the city of Birmingham, where the film was shot, mercifully survives, as does New York City, which is also toast in the film) a gigantic, three pronged spaceship dispenses hundreds of smaller harvester craft who, instead of decimating all of the population, hoover them up, transporting them into pods in which they are trapped, but still alive. Tom, Harriet, Floyd and Samantha seem to be hive mind linked, sharing each other's darkest fantasy nightmares: after the attack the group find themselves stranded on an alien planet. "This isn't home, is it?" asks one of them, and they'd be right. But their abandonment isn't random, and as the oddly assorted group slowly bond in the face of adversity, they become aware that others may be about to give them a higher purpose, particularly Tom, who may final realise his superhero dream.

Invasion Planet Earth is certainly not without its problems. Cox's idea for the movie dates back to 1999, and it was planned for production many times over the next twenty years, before finally being completed at the beginning of 2019. As a result the story lacks a little in cohesion - at times it feels like a DIY Lifeforce. Some of the effects sequences are better than others, and the big screen release it's about to get will show this up which may not go down so well with audiences used to more polished, and way bigger budgeted SFX movies.

But let's stand back a moment from those quibbles and take a look at what we have here. Cox has pulled off an amazing feat: an exciting ID4 style alien invasion movie with a real heart, and a payoff that provides hope among the onscreen carnage. He has assembled a credible cast who keep things very grounded and therefore believable, with special mention for Simon Haycock, a square jawed but fallible hero. Yes it does on occasion have the feel of a Sunday teatime TV series, but that's not a criticism: H G Wells's 'War of the Worlds' was as homespun as you like (it was the movie adaptations that removed the home-counties-in-peril atmosphere of the book) and in some ways Cox's film retains that domesticity, while adding in some very Arthur C Clarkean concepts. That's not to say that Invasion Planet Earth doesn't have spectacle: Cox reckons around 900 people were involved in the central alien attack sequence. And you have to admire a director whose tenacity had him learning special effects skills - yes the compositing on screen is mainly Cox's work - raising all the finance for the movie and even co-writing the end theme song, although praise is also due for Benjamin Symons' dramatic score. Excellent work all round.

Invasion Planet Earth is released in UK Cinemas from 5th December, Digital Download from 16th December and DVD from 30th December