Sitting down to watch the opening episode of Sky Atlantic's new drama Britannia last night, it was easy to hope that this historical drama about the Romans invasion of the British Isles way-back-when would fill the Westeros-shaped hole in our lives. After the first episode, that did not feel like the case, but it's hard not to see its potential.

Written by playwright laureate Jez Butterworth, Britannia kicks off with Roman General Aulus Plautius (David Morrissey) putting four defectors to rights ahead of the invasion. Already we know that this dude is a power hungry dick of the highest order and instantly root for the face-paint loving, bonfire-worshipping nutters across the sea that are the Celts, because that lot look like they are having some serious craic - that first half-hour looked every bit of the Body and Soul area at Electric Picnic circa 3am.

That's probably the main thing to take away from Britannia - almost everyone is high off their chops off some plant or other most of the time - particularly one of the main characters (and there are many) Divis, who believes he has visited the underworld where he was warned about this whole Roman invasion thing and can somehow also go all Derren Brown from time to time and get folk to do what he wants.

Divis finds himself paired up with the young Cait who had her 'becoming a woman' solstice ceremony crashed by those pesky Romans. She spends most of the episode, understandably enough, grieving for the loss of her slaughtered sister and grandfather but you can't help hope she will shake that off soon enough and go all Arya Stark on those invaders.

It also seems the Celts had enough to be dealing with it among their own warring tribes without adding more trouble into the mix. We meet Zoë Wanamaker's Queen Antedia of the Regni Mad Maxing into a wedding between a member of her tribe and a member of an enemies, King Pellenor of the Cantii (Ian McDiarmid). However, things soon go all Red Wedding on us as the groom is taken out and further tribe members arrive with Kelly Reilly's Kerra hiding away in the trees with a bow and arrow.

There's also Mackenzie Crook who looks appropriately weird and terrifying as Druid leader Veran and Irish actor Barry Ward as Cait's father Sawyer who we haven't seen much of yet but will have more prominence later.

There's probably about ten other main characters we haven't mentioned yet because there are just so many of them it's hard to know who is important at this point and who will have an arrow through their chest in the next episode. Britannia threw in a little bit too much plot into its first outing that it left you feeling a bit unattached from the entire story, however there is still enough intrigue there to want to see more, and if they manage to bring a bit of focus to it and nail down the often-shifting tone, it's easy to see how Britannia could start to come into its own.

History books should probably be left on the shelves for this one as there are plenty of inaccuracies to point out but what period drama can claim it doesn't?

All ten episodes are available to watch on Sky on demand so we'll stick with this series for now, at the very least, we'll have some excellent face-painting inspiration for this year's Picnic.