When watched together, Gregory Doran’s Henry IV Part I and II is an engrossing six-hour epic.

Part I opens in complete darkness. A procession of chanting monks enter a Catholic church bearing candles. There is a body lying on the floor under a giant crucifix.

Jasper Britton’s Henry IV dramatically rises from the ground and places a crown on his head.

On the balcony is the ghost of Richard II, a reminder of what has gone before.

This is Shakespeare’s own game of thrones, having himself deposed of the last king; Henry faces open rebellion up north.

Part I offers a panoramic vision of British history. Battles and political intrigue are tempered with the drunken antics of Prince Hal, Falstaff, Ned Points, Mistress Quickly and the rest of their motley crew in the Boar’s Head Tavern.

There is a lovely contrast between the two young Harrys. Alex Hassall’s tall dark and strikingly handsome Prince Hal is a happy hedonist.

When we first see him he has just enjoyed a ménage a trois – as Sir John Falstaff lies in a drunken stupor under the covers of the bed next to him.

Trevor White’s blond mad-eyed hot-headed Hotspur literally leaps into action; yet on a personal level seems churlish and unable to open up to his wise young wife, an emotional performance by Jennifer Kirby.

Sir Antony Sher genuinely looks like he is having such fun as eternal slacker Falstaff – a role he says he had never considered playing before.

His Falstaff is a jolly “white bearded Satan” – ruddy cheeked and gout-ridden. His belly so round that when he plays dead on the battlefield he cannot roll over to get up.

It’s pure comedy gold – no more so when sitting on table in the tavern with a red cushion as a crown pretending to be King, drinking Spanish white wine and trading insults with Hal.

When actor Antony Byrne walked on stage in a Rolling Stone t-shirt, black jeans and boots to take a selfie at the start of Part II, I wasn’t quite sure what was happening.

But it soon became apparent he was the narrator, Rumour, and after a brief modern interlude the action resorted back to period costume.

Further hilarity is provided in the second half of this double-bill by Justice Shallow and Silence – played by Oliver Ford-Davies and Jim Hooper who make an incredibly funny, poignant double-act.

Although there is less action in Part II, it’s all the more colourful. The insane Pistol – a great turn again by Antony Byrne – and Falstaff’s ragbag army of misfits – Mouldy, Shadow, Wart, Feeble and Bullcalf provide more laughs.

We witness the tragic demise of the despairing barefoot king, the rise of valiant Hal – and Falstaff’s sorry downfall.

Henry IV Part I are II are plays of extreme light and shade and this is once again reflected in Stephen Brimson Lewis’s stage design and Tim Mitchell’s beautiful lighting – from the darkness of the candlelit church where Henry IV is crowned to the smoking red sky of the battlefield and golden morning light which bathes Shallow and Silence.

A fascinating watch.

• Henry IV Part I and Henry IV Part II both run until September 6. Details at the RSC website.