John Betjeman wrote to people as though speaking to their face. You feel that he never thought in advance how he might best put things. The natural approach was to please, to be friendly and encouraging to whoever it might be. Official correspondence apart, only one single letter is anything like a rebuke, and it is to the architect Lionel Brett about a television script he should not have shown to others.

To edit these letters was a very tricky task. Candida Lycett-Green has divided them into chapters, to each of which she writes an introduction. This editorial commentary is a model of tact and proportion. Footnotes further explain hundreds of private references, and they are brief. Her affection for her father, and for Penelope, her no less exceptional mother, is completely true, and neither mawkish nor defensive, as it might have been.

Nobody hits a man who makes them laugh is a truism which seems the starting point for many a comedian’s strategy in life, including Betjeman’s. ‘Jokes and Novelties, Book Reviews at Short Notice’, as he jotted on the top of a letter to Compton Mackenzie. Vulnerable, whimsical, in the grip of fantasies about dim poets and dimmer peers, thrilled by recondite knowledge, especially of church matters and architecture, his character committed him to be at home only in an inner circle of kindred spirits. Friends such as Osbert Lancaster, Maurice Bowra, Evelyn Waugh, Patrick Kinross, Alan Pryce-Jones, his publisher John Murray, James Lees-Milne and Cyril Connolly could do no wrong. Where they were concerned, he was – in the words of the hymn – lost in wonder, love and praise. Who else could have addressed John Sparrow, the far from cosy Warden of All Souls, as ‘Darling Spanzbury’ and got away with it?

Primarily an insurance policy, cliquiness is also a bit of an act. ‘He always had the ability to seem helpless,’ Candida Lycett-Green observes. The letters reveal that he had measured for himself the gap between pose and reality: ‘I do love visiting the sick because it makes me thankful I am not sick myself.’ The fact remains that for a dozen years he was a visitor at Bart’s Hospital every Thursday. Kindliness was not the less genuine because of its component of self-seeking curiosity. He sought out Lord Alfred Douglas, otherwise Bosie, and Sidney Mavor, who had been called as a boy witness at the Wilde trial; he thought Sir Ninian Comper and H S Goodhart-Rendell the greatest of men; he was upset by the suicide of Dr Stephen Ward. Innumerable bores and time- wasters were welcome to float in the tide of his career.

‘Fuck the critics,’ he wrote, and the same for The Times, the Americans, and even John Wain, who snubbed his poetry. Leavisites, levellers and preachers of all sorts, the rancorous Geoffrey Grigson and the killjoy Julian Symons despised him. It is a horror that this book’s dust-jacket has a quote from Symons, a real enemy, to the effect that Betjeman was a great eccentric, thus typically appearing to praise while actually being condescending. Unfortunately for him, Betjeman was no good at hating back. The best he could do was along these lines: ‘A dear little kiddy from the slum house next door threw a brick through the window when it was playing at thieves with its sub-normal companions.’

This second volume covers the years from 1951 to 1984, a period when television happened to be growing out of its infancy and had not yet homogenised all character. In many letters Betjeman insisted that television was not an art form but an extension of journalism, and that at heart he was a journalist. In the absence of a live audience he could play to the gallery, and he looked right for the part, a natural. Everybody suddenly became his friend; the whole country was coterie, with him at the centre.

Nobody could have been less political than Betjeman. Some friends were lifelong communists and others were fascists. It was a splendid irony that he came to stand for everything conservative with a small ‘c’. England as he imagined it proved also to be many other people’s England. The reasons why he turned into a household name had to do with his skills and merits but also, I think, because what was really national decay was on all sides being misrepresented as necessary change and even progress. He spoke for everyone who objected to the developer, the accountant and the executives ‘with small moustaches’ feeding as though on a living corpse. It is melancholy to read of the fate of the Coal Exchange and the Euston Arch and many defenceless churches and buildings, but victories of preservation are also recorded here. Success did not go to his head. On the contrary, he felt obligations all the more intensely. He was president or vice-president of seventy societies or associations, and a friend or member of two hundred.

Time and again he refers to guilt and anxiety. This had to do with the opposite sex. He formed schoolboy crushes on Joan Hunter Dunn women, and the most wondrous of them was Mary Wilson. It is highly entertaining to read how he gave her secret assignations in St James’s Park, and visited her in Downing Street, where he found that the red lining of the lift was erotic.

His letters to Penelope were written and spelled in child-speak, often illustrated with drawings and usually signed ‘Yorz trewely, Tewpie’, with echoings from Edward Lear. The new Spalding Top Flight golf-ball had two black dots on it, and he told the wife of the Frilford Heath pro: ‘I couldn’t ever hit those balls, they remind me of my wife too much.’ He called her legs ‘Broadwoods’, after the piano. ‘I love her. But I cannot live with her for long without quarrelling,’ he wrote to an inner-circle friend, Billa Harrod, and added, ‘I cannot bear to hurt her.’

In fact, around 1960 he had met Elizabeth Cavendish, whom he nicknamed Feeble, with many variant spellings, and for whom he reserved inappropriate adjectives like pale, tired, wasted and so on. Harry James was a clergyman in whom Betjeman confided, and he summed up the situation: ‘He went through long periods of being very, very unhappy and consumed with guilt. It was definitely a case of loving two women, I know he loved them both. I did not advise him what to do, he had a very deep love for Penelope but he just could not live with her which made for an impossible situation.’ The older Betjeman became, the more Elizabeth Cavendish took him under her wing.

The practical consequences were that Penelope went for increasingly lengthy trips to Spain and India, and then settled by herself in a house in the Welsh Marches. What had been the Betjeman home in Wantage for forty years was sold, and family life evaporated. According to Candida Lycett-Green, Penelope offered a divorce, which he refused. He had nightmares of exclusion and rejection, such as being shut in a cupboard. But everyone behaved for the best, and their emotions come to dominate the last part of this book. I found it very moving. Under the cheery and pleasing surface, here was the loneliness and uncertainty which found its way into the depths of his poems.