CONTAINS SOME SPOILERS
Hopelessly one-sided debate time: Danny Dyer is rubbish, isn't he? All those films and he's not been any good in any of them. Some of them have been okay, but not because of Danny Dyer: they've been okay in spite of Danny Dyer. For example, I didn't mind Devil's Playground as a reasonably efficient if unremarkable zombie movie, and I enjoyed Severance a lot, but in no way were either of those films enhanced by Dyer's presence in the cast. Certainly he brought nothing positive to Age Of Heroes or Doghouse; indeed his obnoxious characters made the films less enjoyable than they might otherwise have been. On the other hand, in a film as utterly worthless as Basement Danny Dyer was the least of their problems. In too many movies he's been exactly the same unlikeable and foul-mouthed yobbo: blokey, sexist, charmless, and in serious need of a smack round the head with a chair leg. I obviously have no idea how close that is to him in real life, but that's his screen persona and it's pretty deplorable.
Presumably Deviation was intended either to demonstrate Dyer's previously untapped thespian range, or to force one upon him. Here he's having a stab at a fully rounded human being: still charmless and unlikeable but a pathetic whining psychotic rather than a sweary hooligan. Frank (Dyer) is a killer who's escaped from Broadmoor and takes nurse Amber (Anna Walton) hostage in her car as he prepares to flee the country. Can she get away? Will he kill her like the others, and anyone else who gets in his way? And why doesn't Amber just lift the headrest out of its socket?
There are two sides to Frank: he's partly your basic bog-standard homicidal maniac who kills without mercy anyone who crosses him, and partly a mumbling loser blaming everyone but himself for his crimes: they teased him, they provoked him, he's a nice bloke really. Danny Dyer just isn't the actor to play someone so distant from his usual "mouthy git with a sixpack" performance, let alone someone switching between two totally different personalities. Most of the movie consists of his dialogues with Amber - not a bad idea for a film in theory, but this one doesn't make it plausible enough that she would enter into any kind of conversation with him, let alone come close to empathising with him at any point.
So it's astonishingly dull, it's unbelievable, and it's fatally miscast with a leading man who simply isn't up to the job. Might it have been a better movie with another actor in the role? Possibly. Certainly it's no good at all as it stands. Incredibly, this utter tosh got a British cinema release (albeit a limited one).