Benedict Cumberbatch on The Hollow Crown, bloody warfare and discovering he's Richard III's cousin

In a fiery speech, ‘mad Margaret’ curses everyone around her. The worst of her fury is reserved for Richard (“Thou elvish-mark’d abortive rooting hog! “. ) Watching Cumberbatch blench under this attack on his character’s physical deformities, you find yourself moved to stand between theatre’s blackest villain and his tormentor.

Cumberbatch plays Richard III in the last two parts of The Hollow Crown - Henry VI Part II this Saturday and in Richard III next Saturday. The landmark BBC2 series is epic in scale and boasts a cast that includes Hugh Bonneville, Michael Gambon, Keeley Hawes and Samuel West - and Andrew Scott, Cumberbatch's old Sherlock nemesis Moriarty, makes an appearance as King Louis.

It was partly the sheer scope of the project that persuaded Cumberbatch, arguably the most in-demand actor of his generation, on board: his faceted performance of the Bard’s "bottled spider" is helped enormously by the fact that viewers have, in the course of the series, witnessed the events that shape Richard’s psychopathy.

“I took the part because it has some of the most extraordinary, visceral, gut-punching language and action that you get in any of Shakespeare’s dramas," says Cumberbatch. “Richard III is a tragedy, but you only really appreciate that tragedy if you have seen Richard through all the plays and have met the adolescent who becomes the despot who becomes the regretful, nightmare-haunted wreck before he dies in battle.”

The exhumation, in 2012, of the remains of Richard’s body in Leicester allowed unprecedented authenticity in the matter of the king’s hump ( Cumberbatch is shirtless in an opening scene of next week's Richard III); a prosthesis was created which replicates exactly the spinal scoliosis found on the skeleton. Things got spooky, however, when scientists working on the king’s remains shared a new discovery with Cumberbatch.

“It was an extraordinary bit of serendipity, as I was literally dressed as Shakespeare’s version of Richard III when I received an email from Leicester University saying that I was a not-altogether-ridiculously-distant descendant of Richard. I’m a third cousin sixteen times removed, which is still distant, but puts me ahead of an awful lot of other people. I was asked to read the poem written for the occasion by Carol Ann Duffy at the re-interment in Leicester Cathedral. To have been present when Richard III found his resting place was moving; I was at the burial of a king. “

It’s easy to see the History Plays as a meander through the mists of time, but for Shakespeare’s contemporaries, Richard’s defeat at the Battle of Bosworth Field in 1485 was of lively interest, pivotal to their sense of national identity ( much like today's interest in the First World War). Even for our own time, Cumberbatch argues, The Hollow Crown strikes unsettling chords:

“These films stretch well beyond the remit of historical or period drama," he says. "They are about everything we we’re facing, all the debates about who we should ally ourselves with, whether we should be part of Europe, and how deep these divides go within a society. And the violence of medieval warfare has a resonance with what’s going on with extremism in the world at the moment. To see the headlines, and then read the day’s shooting script, realising we are enacting a beheading, literally taking someone’s head off their shoulders and having it witnessed – sad to say, these are things which are still part of our world. “