Biography: He would toss the script aside and let his imagination soar; there'd be a few crackles of comic lightning and then that familiar slow spiral down into bathos. The first bit was fantastic, Spike, his directors would say, but can we lose the rest? He'd tell them that you got the lot or you got nothing, that he was the best judge of what was funny. And they seldom had the heart to tell him that he wasn't, that he lacked any ability to self-edit.
If they persisted in tactfully trying to extract just the pure comic gold, Milligan simply went to another place. "His eyes would become heavy and close," director Joe McGrath told Humphrey Carpenter. "You could see the blood drain from his face, and he'd become haggard - have no energy and just sit staring into space, and it would become impossible to get him to go on. He just had to be helped to the car."
Spike Milligan's story is of paradise lost twice over and forever regretted. The son of a British Army sergeant, Sligoman Leo Milligan, he was born in India in 1918 and lived there until he was 15. "Spike is still a child," said psychiatrist Anthony Clare. "He never grew up; he stopped when he came to England. It was so gloomy and disappointing to him that he wanted to remain the child he'd been in India. So he kept his ability to think like a child, seeing the world in simplistic terms with maddening innocence."
A neat little bite of pop psychology from Dr Clare, but nonetheless convincing. Milligan got as close as he ever came to true happiness in the company of children, his own or anyone else's. And he certainly spent his long life mostly behaving like a wilful child.
His second paradise was lost in 1960 when The Goon Show ended its nine-year run on BBC radio. He said he wasn't sorry to see it go, and often blamed the workload involved for his manic depression, but in 1954 he acknowledged it as his "life's work". And what a towering comic achievement The Goon Show was! It is clear that Milligan was the show's only begetter; his exploration of Goonery went back to his own army days, when he became fascinated by strange creatures called Goons in the old black-and-white Popeye cartoons, and started doing Eccles-type voices to amuse his fellow-soldiers.
Trying to earn a living as a dance band trumpeter in drab London after the war, he drank in Jimmy Grafton's pub, where he met and teamed up with struggling young comics Peter Sellers, Harry Secombe and Michael Bentine. The shows that resulted from this fortuitous meeting of minds, nearly always written by Milligan, revolutionised radio comedy and were worlds away from the cosy domestic sitcoms and rehashed music hall routines that had been mainstays of the BBC. Drawing on his love of movie cartoons for The Goon Show, Milligan realised that radio was an area where the impossible could happen. He said that the pictures on radio were better because they happen on the other side of your eyes. Where else could Minnie Bannister descend an almost endless set of staircases to answer the front door, even though she lived in a bungalow? Or Eccles, told that the log he was crossing a river on was a crocodile, say "Oh - I wondered why my legs were getting shorter"? He never equalled this achievement - but, then, neither has any other radio surrealist.
Not that Milligan's 40-year post-Goons career is in any sense a story of decline, of course; he went on to fresh triumphs as a stage performer, poet, novelist and author of many volumes of memoirs (most of them containing much evidence of his inability to know when to draw the line), and recaptured some of The Goon Show's glory in TV series such as Q and The World of Beachcomber. He also became a tremendous pest as far as the BBC was concerned, continually bombarding department heads with complaints and demands. His campaign to be considered as a presenter of Housewives' Choice (for which he would have been wildly unsuitable) lasted for five years.
Humphrey Carpenter, distinguished biographer of W.H. Auden, Benjamin Britten, Ezra Pound and J.R.R. Tolkien, has here produced a work that is vaguely unsatisfactory, light on true insight into this fascinating and wayward man and heavy on salacious indiscretions. As well as the offspring from his three marriages, Milligan fathered two "love children" (as the tabloids called them) and the final section is unbalanced by a very dull interview with one such and his mother - taped only after a formal contract had been drawn up and financial terms agreed. Then there are Carpenter's regrettable little attempts at Goonery - starting the book with some nonsense about a jelly-filled sock, and unfortunate phrases such as: "This biography gets more and more exciting as it goes on, folks!"
Milligan's puzzled regard for humanity was evident in almost all his output, in spite of his personal misanthropy. And, as with all great artists, it is the work that is important. Even though he behaved so badly to so many people, surely no one could have wished upon him his actual real-life predicament: he lacked the simple ability to be happy (except for a few moments here and there with his beloved children). In a letter to his friend, the poet Robert Graves, he claimed that even when the depression lifted he wasn't happy. He could make anyone laugh except himself.
Better to remember him as the late Harry Secombe did, talking about those Sundays recording The Goon Show half a century ago: "It was a time for hysteria and brandy, for soaring upward on the thermal currents of Milligan's imagination, a time for wishing every day of the week to be a Sunday."
Stephen Dixon is a critic and artist
Spike Milligan: The Biography. By Humphrey Carpenter, Hodder and Stoughton, 435pp. £20