David Tennant celebrates 400th anniversary of Shakespeare's First Folio

David Tennant bounds into the room, friendly, super articulate and energetic.

The actor and Doctor Who favourite, regularly voted the best Doctor by fans, is set to appear once again as the Time Lord in the forthcoming 60th anniversary specials.

The ongoing actors' strike prevents him from talking about those (Doctor Who is now a BBC/Disney co-production and US actors' union Sag-Aftra has been on strike since July).

But we're together, in a room full of books and leftover croissants - clearly actors need sustenance - to talk about Shakespeare, a playwright Tennant calls a "genius" who "had a particular sense of what it is to be a human" and expresses it "in a way no one else really does".

Tennant, who is an associate artist with the Royal Shakespeare Company, is steeped in the Bard. One critic described his Hamlet, which aired on the BBC in 2009, as "theatrical history in the making".

He excelled as Romeo and Richard II and, when we met, had just finished his first day of rehearsals for an already sold out run of Macbeth at London's Donmar Warehouse.

He's no-nonsense about the superstition of only referring to this most atmospheric work as the "Scottish play". Tennant freely uses the word "Macbeth".

But he admits to terrible nerves ahead of the show - however successful you are, it never gets any better, he says.

Renowned actors have been in his shoes; famously Lord Olivier was Macbeth to Vivien Leigh's Lady Macbeth in 1955, Sir Ian McKellen and Dame Judi Dench had their turn in 1976 and Sir Antony Sher and Dame Harriet Walter in 1999.

For Tennant, Shakespearean roles are like "Olympic events for an actor".

"The idea that you're being invited to stand next to these greats and sort of challenge yourself, test yourself against them and see if you've got something new to bring to that… that's part of what's exciting about it."

West Lothian-born Tennant "always wanted to be an actor" (his childhood obsession with Doctor Who had a big part to play in that) and from the way people talked about the plays, "I knew there was something magical about Shakespeare."

But that didn't mean he was immediately hooked when introduced to Macbeth at school - although he's at pains to praise his teacher.

He says the plays were written to be performed and it's "a shame that the first experience of Shakespeare is sitting in a classroom, trying to mouth these words that don't sit in your mouth and don't necessarily make a lot of sense to you at the age of 14".

"That's why a lot of people fall out of love with Shakespeare before they've really had a chance to fall in love."

Tennant fell in love when TAG, a Glasgow theatre company, brought As You Like It to his school's assembly hall. "I didn't necessarily understand every word and some of it felt perhaps a little unnatural and foreign to me". But the teenage Tennant was transported "because it was live and it was happening".

Now his head is brimful of a play that opens with three witches plotting and takes us on a journey of murder and guilt. Tennant says Shakespeare's take is "incredibly modern".

"The way he expresses Macbeth's fear of never sleeping, the torture of being in the restless ecstasy of never being able to close your eyes."

Even for Tennant, though, Shakespeare needs decoding. He tells me, when he opens one of the plays, he "100%" puts the modern translation next to the old. He deciphers the language so theatre audiences don't have to.

"If we're doing our job halfway properly, you shouldn't have to worry about understanding every syllable. You will be transported by it."

There can, though, be layers of meaning that still surprise you 10 weeks into a run, he says. "Usually on a wet Wednesday afternoon matinee, you'll suddenly go 'oh, that's what that line means.'"

Macbeth is one of 18 Shakespeare plays that would have disappeared if, seven years after his death, the actors John Heminges and Henry Condell hadn't published their friend's greatest plays in the First Folio.

That book was the first time the plays had been put together.

Before then, only 18 had been printed, in small paperback editions known as quartos.

The First Folio was registered for publication on 8 November 1623.

There were 750 copies made. Without it, we could have lost all the unprinted plays, around half of Shakespeare's works, including not just Macbeth but Julius Caesar, The Tempest, As You Like It and Twelfth Night.

Four hundred years on, 235 original First Folios are known to survive - 150 are in the US, and about 50 in the UK and Ireland.

Tennant says: "The reason that those plays are still performed around the world and the reason that Shakespeare is the cultural colossus that he is, is because that book was published."

To celebrate the anniversary of the First Folio, the Royal Shakespeare Company launched a nationwide playwriting initiative, 37 Plays, to seek out the country's most promising new writers. The 2,000 submissions were whittled down to 37 which the RSC believes capture the soul of our age, in honour of Shakespeare's own 37.

Georgia White, the RSC's head of national partnerships, said there are links between what Shakespeare was writing about and the issues tackled in these new works "to do with class, to do with faith, to do with conflict and war.

"Even though it was 450 years ago, society is still facing similar big challenges and big issues," she adds.

Tim Wallers, an actor turned playwright, wrote The Doris Effect, based on a true story of how a renewable energy company's plans split his rural Shropshire community.

It was performed in a staged reading at the New Vic Theatre in Newcastle-under-Lyme.

In his play, Wallers gives King Lear's "Blow winds and crack your cheeks!" speech a modern spin. Shakespeare's "til you have drench'd our steeples, drowned the cocks!' becomes "til you have drenched our solar panels and drowned the council who put 'em there".

Wallers said the nod to Shakespeare was because both Lear and his character, Doris, are raging against what's happening around them.

His play, he told the BBC, is a "microcosm for what has happened in the nation, which happened in our community, which is divisiveness, and divisiveness is everywhere".

The winning playwrights from across the UK range in age from nine to 65. Life Goes On, a play by 17-year old Isabella James, was performed script in hand with Silhouette Youth Theatre in Northampton.

It's about the "complex, complicated subject" of grief, a topic Shakespeare explored so well.

He is also credited with inventing around 1700 words that we still use today, as well as phrases that have become part of the language, including:

James, an A-level student says: "That's probably an even better reason to immerse yourself in Shakespearean plays and see what he's written, because he's really impacted not just the words that we speak, he amplifies the importance of the words that we use."

For Tennant, Shakespeare is "weirdly modern" because he captures how complicated it is to be human.

"He writes about the moment he was in, which seems to, by dint of his genius, also be the moment we are in."

Tennant is one of the UK's most exciting actors, known to wider audiences not just for Doctor Who and Broadchurch, but his film role as Barty Crouch Junior in Harry Potter and the Goblet of Fire.

But you get the sense that there's even more magic, for Tennant, in performing Shakespeare.

It's why he is celebrating the anniversary of the First Folio, that book that was the first step in creating a legacy for the greatest playwright in the English speaking world.

The BBC is celebrating the 400th anniversary of the publication of Shakespeare's First Folio with programmes across television, radio, BBC iPlayer and BBC Sounds.