Andrew Lambirth claims that Bryan Robertson was ‘the greatest director the Tate Gallery never had’; but on the evidence of this book, he would have been a disaster — chaotic, hopeless with money and eternally late. What he actually was was the inspired and inspiring director of the Whitechapel Gallery from 1952 to 1969. He also wrote on art and ballet for The Spectator and was an esteemed contributor to The Critics radio programme. But he did not get the Tate appointment he longed for and was effectively forgotten by l990, so it’s a bit mysterious why he is being written about now.

Lambirth is careful to say that his book is not a biography but a ‘compendium of Robertsoniana’ — which is posh-speak for a jumble of old articles, interviews, catalogue introductions, poor-quality photographs and personal reminiscences, thrown together in vaguely chronological order but with no attempt at editing. The first few chapters are like wading through soup, but one gradually gets hooked on the man.

Robertson was a very remarkable character. Born in 1925 to an ‘ordinary’ family in Streatham, he suffered from chronic asthma, which meant he spent much of his childhood in bed reading. His mother would bring him art books from the local library and take him to the cinema. He realised early on that ‘I lived through my eyes’.

He got a sub-editing job on the Studio magazine, went to Paris for a year and was offered a job at the Lefevre Gallery when he was just 23. Then Heffers in Cambridge asked him to set up a gallery over the bookshop and he made a huge success of it, showing Picasso, Matisse, Gauguin, Braque and Cézanne, which led to his appointment as director of the Whitechapel at the very young age of 27. The gallery had almost no money and attracted mainly East Enders and art students, but Robertson insisted on giving them the best. He mounted the first Jackson Pollock exhibition in London, the first Rothko, Jasper Johns and Rauschenberg, but he also showed English Old Masters, such as Rowlandson, Stubbs and Turner, as well as launching new artists in his annual New Generation show.

Everyone agreed he had a wonderful eye and was brilliant at hanging, but his special skill seems to have been boosting young artists, encouraging them to have faith in themselves. He told Keith Vaughan: ‘You must develop some grandiosity of feeling…. Perhaps you should play some Berlioz every morning or hit the bottle or something.’ He wanted his artists to think internationally and not get bogged down in provincialism. (He had a particular hatred of the Euston Road School, which he described as ‘full of ex-public school boys painting their cleaning ladies’.) But he was also good at rejuvenating mid-career artists, such as Barbara Hepworth and Prunella Clough, when they were feeling overlooked and despondent. He was keen on women artists altogether, and felt they didn’t get their fair share of attention.

He claimed to be bisexual — and indeed is supposed to have proposed to Bridget Riley at one point — but he was mainly a rather discreet homosexual. He lived for a while with the writer Colin MacInnes (the author of Absolute Beginners) but it is not clear that they were lovers. He enjoyed cooking at his home in Barnsbury, but his dinner parties were notorious because he would invite people for eight o’clock and only start cooking at 11, by which time everyone was legless.

Similarly, he would never start writing an article until it was actually due at the printers and editors were screaming at him. He used his asthma as an excuse. He was completely insouciant about money: he always took taxis and dined at expensive restaurants even when he was flat broke, and he often ‘bought’ paintings without actually paying for them. He never opened his mail, so that plenty of uncashed cheques were found after his death. He also once found a big cheque in the fridge, where he had put it for safekeeping two years earlier. Luckily it was still bankable.

His financial unreliability was his undoing once he left the Whitechapel. He was appointed to set up a new museum in New York State, but the trustees were alarmed when he ran wildly over budget, and furious when he ordered a grove of mature weeping willows to be planted as background to a Barbara Hepworth sculpture.

He mounted a much admired Dufy exhibition at the Hayward in l983, but that was his last major achievement and he lived for another 20 years. He subsisted on occasional bits of freelance work and selling his art collection, including works he’d never paid for. He emerges through the fog of Lambirth’s disorganised pages as a most lovable but impossible man, adored by a whole generation of British artists. This book would have found a larger readership if it had been published 30 years ago.