Britannia, Sky Atlantic review ★★★★★

If – as the old saying goes – you’re only as good as your last job, then Britannia creator Jez Butterworth should by all accounts be the very best.

Last year, the Olivier Award-winning playwright wrote The Ferryman at The Royal Court and it was ‘the best thing we’ve seen all year’.

Well, until his next big thing, Butterworth will cease to be known as the mastermind who brought internal conflict to the stage, and will instead have a reputation as that crazy guy who had a psychedelic trip and wrote a mad – and bad – show vaguely inspired by Celtic history for Sky Atlantic.

‘I remember the first few times I took mushrooms, I saw a lot of images that I recognised from cultures from a long time ago. It’s like this connection to the past, a way of envisioning that struck me as fundamental to the series,’ he said.

If he hadn’t told us this was what he got up to, we might have guessed anyway.

Britannia trailer

Britannia is ostensibly based in ancient history. Set in Britain in 43AD, the brutish Imperial Roman Army is re-invading Britain following Caear’s unsuccessful attack. Crawling over Britain's green and pleasant land (although Britannia was actually filmed in the Czech Republic) are heavily tattooed Celts; muscular, murderous Romans; and vicious, magical Druids.

There’s the a sprawling cast of characters (whose names you won't remember) casually engaged in violence, loveless sex, terrible banter, mysticism and rubbing themselves in mud. It all becomes too weird, too quickly, for the storyline to carry you away.

David Morrissey of The Walking Dead fame hams it up as a Roman leader, and gives the character a flat, two-dimensionality. Zoë Wanamaker and Kelly Reilly (from Peaky Blinders season one) play angry Celtic royalty, and Mackenzie Crook is transformed into a revolting magical Druid – with a really nasty skin condition. Everyone shouts, spits and takes a lot of drugs.

It's not difficult to see why Britannia is the fantasy epic series that was billed as the next Game of Thrones. Unfortunately much of what Butterworth has created is utterly derivative.

Perhaps the most sympathetic character, a young Celtic teen called Cait, is a straight rip-off of Game of Throne’s Arya Stark. Meet a girl who has no name – seriously, as in ‘a girl has no name’ – and who watches her family be brutally murdered and is then befriended by a gruff older man who she also hates. Remind you of the Hound at all?

Fingers crossed that the nine-part series gets better as it follows the power struggle between the Celts, Druids and Roman army. But we won't be holding our breath. Bring on 2019 and the next series of Game of Thrones. Until then, stay off the drugs, kids.