SOMETIME in 2014, I was reading Yvonne Cloetta’s memoir of her life with Graham Greene when I came across a chapter dealing with his relationship with the Soviet spy Kim Philby, who she described as the “one man for whom Graham committed himself totally.”

This sparked my interest, as I knew about Greene and I knew about Philby but I didn’t know that they’d been friends, ever since Greene had worked under Philby at MI6 during the war. Or that Greene had been the only person to defend Philby after he defected to Russia in 1963.

Or that Greene had been to see him in Moscow in the late 1980s, thus satisfying Philby’s long-standing and publicly stated desire “to sit across a table from Graham Greene with a bottle of wine between us.”

Of that meeting in February 1987, all Greene was prepared to say to his biographer was “we had a private dinner. I went by myself to his flat but I won’t say anything about that.” So I decided I would try to imagine it in what became my new play A Splinter of Ice.

As I had been to Moscow on a school trip in the summer of 1985, just 18 months before the evening depicted in the play, I didn’t think it would be helpful to go there again and might even cloud my memory.

But I did do lots of other research, of course, reading every book on Philby and Greene I could get my hands on and ordering copies of their brief unpublished correspondence held at Georgetown University.

And I watched George Carey’s terrific documentary The Spy Who Went Into The Cold, in which Rufa is interviewed in the KGB flat she still lives in and in which the play is set.

There are many books about Philby but three stand out. Firstly, John le Carre’s condemnation of him in his Introduction to The Spy who Betrayed a Generation (1968), which Philby said caused the KGB to finally allow him to publish his own autobiography, My Silent War, later in the same year.

Then there’s the historian Hugh Trevor-Roper’s short book, The Philby Affair (again 1968), also an attack but a less vicious one since Trevor-Roper had known and liked Philby when they worked together at MI6.

Particularly helpful to me though was his last wife Rufa’s love-fuelled 1999 memoir, The Private Life of Kim Philby, which became a useful source for the play in which she also features — she’s played in the online version of the production by Sara Crowe.

After finishing the play, I met the producer Alastair Whatley by chance through a mutual friend and he originally programmed it to start a tour last autumn.

But one positive outcome of the Covid delay for us was the appearance late last year of Richard Greene’s (no relation) excellent biography of Graham Greene, Russian Roulette, which the extra time allowed me, Oliver Ford Davies — playing Greene — and the director, Alan Strachan, to absorb before rehearsals began.

The focus of the play is on the relationship between the two men, which had originally been forged in St Albans during the second world war when Greene worked under Philby (played by Stephen Boxer) at MI6.

Greene later said they were both “men of the left” and “anti-fascist” but he didn’t know that Philby was a communist.

In fact, it was Greene not Philby who had been a member of the party. He’d joined during his time at Oxford in the early 1920s but only for four weeks and he later said it was just a joke with a friend to try to get themselves a free trip to Moscow.

Greene’s later politics could perhaps best be described as contrarian, rather than committed. But he did admire Philby’s commitment and, in his foreword to My Silent War, compared him to the “Catholics who, in the reign of Elizabeth, worked for the victory of Spain.”

Le Carre said he did “not much believe in the political motive of Kim Philby” and saw him rather as “spiteful, vain and murderous.” But Greene absolutely did believe in Philby’s political idealism, which was why he defended him despite the flak he took for it.

In 1987, the year the play is set, AN Wilson wrote in the Daily Mail that for Greene to go “on holiday” with Philby “was like going on holiday with Goebbels when we were at war with Nazi Germany.”

But if Greene was Philby’s chief defender — or “apologist,” according to many — Philby was Greene’s muse. The latter based his 1979 novel The Human Factor on him, as well as, according to Philby at least, his portrayal of Harry Lime in the classic film noir The Third Man.

And, of course, after Philby’s friends Guy Burgess and Donald Maclean — also members of the Cambridge spy ring —  defected in 1951, the hunt was on for “The Third Man,” later identified as Philby, who had tipped them off. So the film became an important element in my play.

When rehearsals finally began in a church hall in Kennington last month, I attended both these and the filming at Cheltenham Everyman Theatre where the play had been due to open.

And it was a joy to watch our brilliant cast inhabit these extraordinary characters and, to my eyes at least, bring them back to life.

The Original Theatre Company's production of A Splinter of Ice is available online until July 31, visit originaltheatreonline.com, and tours theatres nationally from June 8 until July 31.