When his memory was still intact, Ralph Waldo Emerson wrote: ‘We remember that we forget.’ With that in mind, I do small inventories to make sure everything is still clicking. I play old exam pieces on the piano. I recite As Kingfishers Catch Fire. And sometimes, I list the five who spied for Russia.

If I just rolled off the names Burgess, Philby, Maclean, Blunt and Cairncross it would be scant proof that my memory is alive, but I do little mental notes. Because of Alan Bennett’s An Englisman Abroad, Guy Burgess is forever Alan Bates, pudgy, sodden, loathing his grim life in Moscow, longing for his old haunts in St James’s and silk pyjamas from Sulka, shoes from Lobb’s. Oppidan and winner of the Rosebery and Gladstone Prizes at Eton in 1929, too unpopular to be elected to Pop, he won a history scholarship to Trinity College, Cambridge.

Burgess never intended to defect. In 1951, he was considering a request by the Salisbury family to complete a biography of the 3rd Marquess of Salisbury, one of his great heroes, and looking forward to a weekend in Paris with an American he’d met on the Queen Mary when he received the news from Anthony Blunt that Maclean was to be interrogated on Monday, May 28.

On the Friday, Maclean, son of a Liberal MP, educated at Gresham’s Holt and Trinity Hall, Cambridge, was taken out by friends, including Cyril Connolly, for a ‘birthday treat’ of oysters and Champagne in Soho. In the evening, the 38-year-old spy went home to his wife. Half an hour later, Burgess arrived to tell him that that his escape had to begin. Burgess only planned to accompany Maclean as far as France, but the KGB had other ideas.

These details came back with the news that Blunt’s memoir, sealed in a container in the British Library for 25 years, has now been made public. Blunt, Surveyor of the Queen’s Pictures, the ‘Fourth Man’, the talent scout who recruited  Burgess. And also the subject of a Bennett play, A Question of Attribution.

I once felt sympathy for these men. I’d read A Generation on Trial, Alistair Cooke’s account of the Alger Hiss trial in America when I still thought he was the innocent victim of McCarthyism and anti-Communist fever. But the more that was revealed, the more uneasy I became with the young men drawn to spy for Russia through a combination of ideology, peer pressure, complicated notions of morality and disruptive sexual yearnings. It was one thing to fight in Spain against Fascism, quite another to be operating in MI5 and MI6 after the Hitler-Stalin pact.

Nowhere in his memoir does Blunt express regret at lying to friends, recruiting agents and passing secrets to Moscow. He regrets getting found out, being stripped of his knighthood. The fastidious art historian doesn’t know the difference between regret and remorse. Mr Bennett believed that Blunt should’ve been allowed to keep his knighthood because the honour was for his contribution as an art historian, that little evidence exists that ‘Blunt did any substantial damage’. His comments infuriated Cooke, who rejected as ‘fanciful in the extreme’ that Blunt was on the lower rungs of traitorous espion-age, insisting that a man’s expertise on Poussin ‘does not diminish or cushion his responsibility for sending countless decent people to their deaths’.

We will never know the extent of their damage. By learning the West’s atomic secrets, the Russians felt capable of arming Kim Il Sung, setting the stage for the Korean War. That’s enough to wipe the dreamy face off any account. Or as Coral Browne, the English actress who meets Guy Burgess in Moscow, put it: ‘Outside Shakespeare, the word “treason” to me means nothing only you pissed in our soup and we drank it.’ To re-phrase Emerson, I don’t think we should forget to remember.