Womaniser! Depressive! Junkie! By George!

He screwed," David Bret told me, as we waited for a car in his local minicab office, "like a tiger until dawn." This remark prompted a slight but discernible shuffling among those ahead of us in the queue at Company Cars, Pontefract, whose customers seemed unused to hearing matters of passion so directly addressed in mid-afternoon. George Formby? "Rudolph Valentino," said Bret. "Somebody said that about his affair with Ramon Navarro. The thing is," he added, "I've seen tigers do it. But not until dawn. I mean - they're very quick, tigers, aren't they?"

This sort of bold inquiry is typical of Bret, who wrote his first book in 1986, and has since produced, with impressive frequency, sensational biographies of stars, including Valentino, Freddie Mercury and Marlene Dietrich.

Bret's writing is not universally treasured by Britain's academic elite, and he has been attacked by relatives and friends of previous subjects. His book on the rock singer, Morrissey, had him nominated as Bastard of the Year by a music paper. Such disharmony, however, is likely to be as nothing to the reception of his most recent work, published later this week.

George Formby: A Troubled Genius is described in its press release as a shocking work which presents "a very different Formby from the one known to his fans". This is no idle boast: as well as Formby's known preoccupations - horse-riding, gardening and the banjo-ukulele - Bret seeks to add others, including adultery (in one case with a lesbian), homosexual in-jokes in his films, and a period of morphine dependency. This last suggestion - as well as possibly identifying the mysterious substance so ardently endorsed by Formby in "Auntie Maggie's Remedy" - has caused controversy in the George Formby Society, which meets every three months in Blackpool to celebrate the life of the singer, who died in 1961. Its 1,000 members are similarly unenthused by Bret's claims that the singer of "Happy-Go- Lucky-Me" was a depressive, repeatedly treated for mental illness.

Bret - whose previous subjects have almost all been gay icons - led me into his small terraced house on the outskirts of Pontefract, where he lives with his wife, Jeanne, and their son. It also accommodates three dogs, three hares, four rabbits, a hedgehog and a cockatoo, most of which have the run of the place.

The writer, who is in his late forties, had his first contact with celebrity as a fan, then "dogsbody" - to use his word - of the mad Welsh singer Dorothy Squires. At the top of the stairs is a photo of what appears to be a naked bodybuilder in handcuffs.

A prime source of conflict in Formby's life, Bret told me, was his wife and manager, Beryl, a former clog dancer six years his senior. Alcoholic in later life, and with a Bilko-esque attachment to money, Beryl emerges from the book as having controlled her husband with a rigour that would have done credit to the Third Reich. In the ranks of the faithful, there was, predictably, unease when Bret was reported to have described the late Mrs Formby as "a cow". "Everybody said the same about Beryl," Bret told me. "So she must have been a real bag, mustn't she?"

Before he took to biography, Bret worked for Millets, the camping store, then in NHS administration in Yorkshire. It was the latter job, he said, that allowed him access to Formby's medical records, with the help of an unnamed worker at the York hospital that treated the singer.

Bret claims George Formby's case notes reveal that, when admitted to hospital for a month in 1949, the artist was "depressed and rundown". According to the biographer, Beryl told them to "`keep him in there for as long as it takes. And if it takes forever, then he is there forever.' It says that," he added, "in his notes."

Perhaps the most astounding allegation in the book is that, when the star was treated with morphine following his first heart attack, also in 1949, "Formby," as Bret writes, "would soon... but only temporarily, become addicted... There was a period of about four years," he suggested, "when George Formby was on morphine. I think it was intermittent. But he did get addicted."

How could he know? "Well," said Bret, "this was in the medical notes." Could he show me these medical notes? "I didn't read them," he replied. "I had them read out on the phone." Formby, I suggested, seems to have coped amazingly well, considering the paralysing effect the drug has had on other artists. "With Edith Piaf," Bret argued, "the morphine period brought out the best work." Morphine period? George Formby?

"Yes," he said, "I would think so." Formby, he added, was "a suicide case at one point". Formby's medical history is one of several aspects of this book - which consistently fails to name its sources - that would have made it difficult to publish if the subject were still alive, and could sue for libel.

To view a Formby film like No Limit today, 60 years on, is to be reminded of how its star's manic bonhomie has become weird and dislocated with time. Formby is the personification of a kind of naive decency, often exhibited by documentary interviewees from the period, which has virtually disappeared from British life - even in fiction.

Bret's arrival in the lives of the George Formby Society represents what is essentially a generational clash between thoroughly modern biographical ethics and old-world gentility.

Decadence and camp excess are the qualities which draw Bret most powerfully to a subject. Within 10 minutes of our first telephone conversation, he was about to describe some unspeakable act involving an omelette and Errol Flynn, but had to break off because "the rabbit is chewing the phone lead".

Most of the members of the George Formby Society, on the other hand, openly mourn the passing of an age when a man's career could be celebrated without having to confront the more lurid aspects of his intimate life. (Ironically, Formby - with his little ukulele, his stick of Blackpool rock and his marlin spike - remains unchallenged by any other British entertainer, living or dead, in the matter of routine public allusion to his penis.)

I first attended a meeting of the George Formby Society by accident when I stumbled upon their summer convention at the Blackpool Winter Gardens in 1992. For the duration of these weekend meetings, the members - some remarkably young, but all armed with a banjo-ukulele - play songs like "When I'm Cleaning Windows" and "Leaning On A Lamppost" over and over again. To watch this is an experience that can inspire, in an unbeliever, not so much boredom as a sapping of the will to live. It goes on all day, with occasional breaks for screenings of Formby films

and song tuition (where, I like to think, aficionados are given advice such as, "You're coming in too early with your wink"). After midnight, their time is their own, but most seek out hoteliers untroubled by all- night strumming. Recent articles in the society's magazine, The Vellum, have headlines such as "George Formby - A Religion?" and "Formby Picture Healed My Back".

Society members got wind of Bret's book last year, thanks to an article by Jacqueline Morley in the Blackpool Evening Gazette. A volley of furious letters ensued; one writer offered "to thrust a stick of Blackpool rock where the sun don't shine". In an open letter to The Vellum, Bret denied the Gazette's story, saying he had been misreported.

However contentious Bret's reading of Formby's life, he has turned up details which will astonish even the star's most obsessive admirers. On a visit to South Africa, for instance, the couple, who insisted on performing to black audiences, were thrown out of the country after Beryl received a call from Daniel Francois Malan, and invited the father of apartheid to "piss off". Formby's record as a wartime entertainer makes it especially surprising that, as Bret recounts, he was summoned in 1943 by the Government's Dance Music Policy Committee, the body responsible for vetting musicians for collaborationist tendencies.

The committee considered several Formby numbers from the film Bell Bottom George to be potentially sympathetic to Hitler - among them "Swim Little Fish". According to Bret, Bell Bottom George is actually "a potent exercise in homo-eroticism, revered by George's surprisingly large gay following in wartime Britain".

Was it conceivable, I asked one elderly member of the George Formby Society, that the star of Much Too Shy might emerge as a gay icon? "George?" he said. "Gay? So far as I know, his hobbies were chiefly mechanical."

Curiously, the tragic end of Formby's life, documented by the press at the time, provides the fewest surprises. Beryl was diagnosed as suffering from cancer in 1955, and consoled herself with a bottle of whisky a day. Her husband, says Bret, often matched her glass for glass. Two months after her death, on Christmas Day, 1960, Formby, then 56, became engaged to a young schoolteacher, Pat Howson. The singer himself died of a heart attack on 6 March 1961, two days before they were due to marry.

Shortly before Beryl died, Formby is known to have fallen for a chanteuse called Yana. Her stage name hinted at an exotic past in the Orient, but Yana's mysterious life in the East had, in fact, begun in Romford as Diana Guild, a hairdresser's assistant. Displaying the unusually keen eye for sexual ambivalence which characterises his work, Bret asserts that Yana (who was, as her 1989 Daily Telegraph obituary noted, "thrice married") was "blatantly lesbian".

It is hard to predict how the hardcore Formby fans will react when the book comes out. Some feel these things keenly: there was an incident a few years ago when BBC2 showed a drama from the Netherlands which, loyalists felt, was disrespectful to Formby's memory. One member wrote to The Vellum complaining about Formby's name being "bandied about by Dutch perverts". Such "examples of the sick", he added ominously, "convince decent men and women of the need for a cleansing operation." The disquiet at Bret's remarks about Beryl subsided after his letter to The Vellum, in which he said he had been misrepresented by the Blackpool Gazette.

This may not be well-founded. "I said a little bit too much to the Gazette," Bret told me. "I said Formby's wife was a cow, and one thing and another, and the reporter put it all in. I think, to be honest, that I must have said all those things."

The prospect of serious conflict at the society's Blackpool convention this weekend would seem to have been averted: Bret will not be attending as he had planned, after another report quoted him as saying that he had "little to fear from men wielding ukuleles".

Several people I spoke to speculated about what Formby himself would have made of all this. There were 100,000 people lining the streets at his funeral, but his star was hardly riding high when he died. "I think he'd have been astonished - absolutely amazed at the depth of feeling there still is for him," said Dennis Taylor, president of the George Formby Society.

As to the controversy over Bret's biography, another fan told me: "It's traditional to remember entertainers by their catchphrases. Listening to all this, I imagine George looking down from heaven, and giving one last, defiant cry of `Never touched me'."

`George Formby: A Troubled Genius' by David Bret is published by Robson Books on 26 June at pounds 16.95.

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