Breath of fresh Eyre: Turning 70 hasn't slowed down the director as he takes on six shows in 12 months

Richard Eyre turned 70 last March and to say that he shows no sign of a drop in productivity would be a major understatement. By the time he has directed Stephen Ward, Andrew Lloyd Webber's new musical about the Profumo scandal for its opening in December at the Aldwych, he will have chalked up a remarkable run of six theatrical productions over a 12-month period.

The sequence began with Eyre's spare, exquisitely modulated staging at the Almeida of The Dark Earth and the Light Sky, Nick Dear's sensitive, insightful play about poet Edward Thomas, and continued with acclaimed revivals of Simon Gray's Quartermaine's Terms, starring Rowan Atkinson in the West End, and of 1950s Broadway musical The Pajama Game, at Chichester. In early autumn, he will direct Ghosts, his own new version of the Ibsen classic, with Lesley Manville as Mrs Alving and Will Keen as Pastor Manders, for Michael Attenborough's farewell season at the Almeida.

I caught up with him during rehearsals for his current project – a zestful rediscovery of Liolà, an early, rarely performed play by Pirandello, now previewing in the Lyttelton as part of the National Theatre's Travelex £12 initiative. If Eyre was feeling any strain from his unrelenting workload or the oppressive heat, then the relaxed figure who sat opposite me sipping green tea at the Jerwood Space has got the knack of disguising it down to a fine art.

It was here that he spent his 70th birthday, "rehearsing The Pajama Game with a cast in which one of the performers was 22. But it's one of the things that attracted me to the theatre in the first place, that democracy of age. When I became an actor, I thought how wonderful it was to be in the same room as the old guard and to be treated more or less as an equal."

Where some directors of his vintage are driven by the exigencies of paying alimony or by personal unfulfilment, Eyre's wide-ranging career (in theatre, film, television and opera) has been sustained by a long and happy marriage to Sue Birtwistle, TV producer of Pride and Prejudice and Cranford, and he is now the doting grandfather of Eve and Beatrix, the young children of his novelist daughter, Lucy.

We talked about how Liolà may come as a bit of a surprise to people who think that they have Pirandello pinned down as the passionately cerebral playwright of Six Characters in Search of an Author and Henry IV, obsessively trading in such themes as the fluidity of identity, the deceptiveness of reality and the relativity of truth. "There's no meta-fiction in this," says Eyre, who points out that "Pirandello is like Chekhov in being a late starter in the theatre. He was nearly 40 by the time his first full-length play was put on." Liolà has more in common with the short stories about rural Sicilian life that the author had written before his star rose as a dramatist.

In similar vein, we chatted about how seasoned Eyre-watchers may have been slightly taken aback by the announcement that he is to be at the helm of the latest Andrew Lloyd Webber blockbuster. In National Service (his diaries about running the NT from 1988 to 1997) and in Changing Stages (the book about 20th-century theatre that he wrote with Nicholas Wright), the references to the composer are not exactly unctuous. One of his strictures there is that Lloyd Webber's musicals "have had a global success precisely because their 'voice' can't be identified as British: it's universal, an Esperanto spoken by cats in Cats, trains in Starlight Express, Argentinians in Evita, French people in Phantom of the Opera, film-folk in Sunset Boulevard. Or, as Tim Rice put it: '99.9 per cent of the people on this ghastly planet want to see huge mega-musicals and couldn't give a stuff what language they're in'".

Riposting that, "I really take Andrew seriously", Eyre promises that Stephen Ward, is "very, very British". It's "a play with music", he says, rather than a sung-through piece (the book has been written by his old friend Christopher Hampton). The proposition is that the principal victim of the scandal was not John Profumo, the disgraced Minister for War, but Stephen Ward, the society osteopath who introduced him to Christine Keeler. Because, in his private life, Ward was a harbinger of the nascent permissiveness, he provided a convenient scapegoat for a vindictively hypocritical Establishment. Charged with being a pimp and with living off immoral earnings, he was driven to suicide on the last day of what – with its forced confessions and fabricated evidence – was virtually a show trial.

"It's Stephen Ward's story," says Eyre. "He's the narrator and the protagonist." He agrees that, in some ways, Ward was his own worst enemy. "The connection with MI5 was genuine, but in his mind, he saw himself as a broker between East and West, capable of saving the world from nuclear disaster." A friend to stars and royalty who had treated everyone from Gandhi to Ava Gardner, he was a confirmed show-off and when the story started to focus on him, instead of keeping his counsel, he couldn't be restrained from blabbing about his role in it. "But I was talking to an actress the other day who knew him very well and she remembered how terribly kind he was to people. There is no question that he was stitched up" – and the sordid alliance between the press and the police gives the material a fresh topicality. Asked what Lloyd Webber's music will bring to the proceedings, Eyre refers to "a particular combination of astringency and romanticism".

Hypocrisy about sex, which in Stephen Ward "acts as a metaphor for hypocrisy about everything else", is a much more combatively acknowledged business in Liolà, Eyre first became fascinated by Pirandello's Sicilian short stories in the mid-1980s when, during a visit to Venice, he saw the Taviani brothers' celebrated movie Kaos, which loosely dramatises four of them. They summon up a world of stony landscapes, rural communities starved of the young men who have been forced into emigration by poverty, and of a certain bleak, poetic humour. Pirandello described his 1916 comedy Liolà – which is presented here in a new version by Tanya Ronder and by an all-Irish cast – as "full of songs and sunshine... so light-hearted that it doesn't seem like one of my own works". But under the gaiety, these harsh conditions still make themselves felt.

Tight-fisted landowner, Simone (James Hayes), whose almond crop the women have assembled to harvest, has no heir to whom to leave his money. So it's galling for him that the sexy, carefree labourer, Liolà (Rory Keenan), has three sons by as many girls and takes responsibility for their upbringing, especially given that Simone's dutiful young wife Mita (Lisa Dwyer Hogg), abused for her supposed barrenness, still harbours romantic feelings for this dishy force of nature. It's a mark of the old man's desperateness that when yet another girl falls pregnant by Liolà, he's prepared to swear that the child is his. But that, of course, sets a precedent that allows our hero both to consummate his love for Mita and restore her to full respect and status in the marital home.

The fun of the piece lies in watching one barefaced deception trump another as vengeful plotters are hoist by their own petard. "There's a complicated moral scheme," Eyre explains. "You think you know where true north is, but the compass keeps rotating. Everybody is in some way in the right and in some way corrupt". As for the easygoing libertine, who blasphemously intimates that his stratagem is "probably the way God took with his precious Mary all those years ago", Eyre says that, "Tanya and I have been playing with the idea that he's a sort of wish-fulfilling alter ego of Pirandello – a man tortured with anxiety about the mental illness of his wife".

From Andrew Lloyd Webber, Eyre plunges straight into 2014 with some Massenet, whose operatic adaptation of Goethe's revolutionary novel Werther he will be directing (with Jonas Kaufmann and Elina Garanca as the leads) at the Met in New York, where he enjoyed great success with Carmen. Disclosing the news with a faintly wry, clinching grin, as though I might otherwise have been inclined to underestimate his productivity, this improbable septuagenarian heads back to the rehearsal room and more of the joys that flow from its distinctive "democracy of age".

'Liolà', National Theatre, London SE1 (020 7452 3000; www.nationaltheatre.org.uk) in rep to 6 November; 'Ghosts', Almeida Theatre, London N1, (0207 359 4404; www.almeida.co.uk) 26 September to 23 November; 'Stephen Ward' previews at the Alwych Theatre, London WC2 (0844 847 2379; www.stephenwardthemusical.com) from 3 December