THE portrait of Winston Churchill, painted to mark his 80th birthday, was one of his wife's worst nightmares come true. Clementine Churchill, who had dedicated her life to hiding the true man behind the statesman's mask, was appalled to see Graham Sutherland's depiction of her husband looking more like - in Winston's words - "a down and out drunk who has been picked out of the gutter" than a British prime minister.

She dispatched the portrait to the cellars of their Chartwell residence and some lime later chopped it up and burnt it.

Winston's protector and wife was a woman smothered in secrets and lies. She was determined to keep the stark, unhappy reality of their family life from the public's claws. The destruction of the portrait was just one of many secrets to be unearthed alter Clementine's death in 1977, 14 years after her husband died of a stroke.

Clementine had a ferocious temper in private, which was concealed in public by her outward calmness, all wrapped up in smiles. "From the outset of the marriage she was fiercely jealous of Winston and could not bear him to show attention to any woman other than herself," writes Joan Hardwick in her forthcoming - biography, Clementine Churchill - The Private Life Of A Public Figure. There were often private, ugly and angry scenes when she accused him of still being in love with two fiancees.

Her ultimate goal in life was to push her husband up to the prime minister's top rung on the political ladder. This task she mastered with the ingenuity, charm and persuasive powers of any successful salesman. "During the time Winston had been in the army she had learnt how to use her good looks and charm to win people to her side," according to Hardwick.

However, all was not to be a bedroom of rosebuds at number 10 Downing Street. Such was, Clementine's emotional disappointment with her marriage that it forced her to contemplate divorce. But she opted to remain a loyal wife, despite their differing political opinions.

One particularly divisive issue for the Churchills was the suffragettes, says Hardwick. "The matter of force feeding had troubled Clementine, as it did many other nonmilitant suffragists . . . she had heard that any woman who refused to eat would be held down . . . a steel gag between her teeth to hold her mouth unnaturally wide . . . and then a tube about four feet in length would be forced down her throat causing extreme irritation. Down the tube food would be poured quickly, causing a terrible choking sensation followed by vomiting even before the tube was removed." Clementine's political muzzle meant that she could only exert her influence on Winston in private on the subject of votes for women.

Clementine's main priority in life lay firmly in carving out her husband's political future and not, as she regretted later, as a mother to her five children.

What is it about politics that sucks the addicts in and spits out fanatical obsessive creatures? She remembered remorsefully how she had enjoyed playing tennis while her children had pleaded with her to return home to her two year old daughter Marigold, who lay dying.

Years later, Clementine was wracked with guilt, again when another daughter, Diana, swallowed pill after pill, killing herself slowly and painfully, alone in her flat at the age of 54. In Diana, Clementine had seen a paler, less beautiful and less effective version of herself as a child.

"But where Clementine had been reserved, Diana was timid and painfully lacking in self confidence," says Hardwick. Diana knew, as did Clementine, that she was the least favourite daughter. "When Diana suffered a mental breakdown it was not surprising that it was against Clementine she turned, going as far as to take a knife and threaten her mother with it ... the shock to Clementine and the realisation of how completely she had failed her daughter was a terrible blow to her sense of herself."

While one daughter was admitted to hospital for treatment for mental disorder, another, Sarah, was arrested three times for drunkenness. Clementine was horrified when Sarah spent a term in prison and furthered blackened the family name.

Her son, Randolph, also an alcoholic, scandalised his mother's "model" family over and over again Winston had spoiled his heir lavishly, yet Clementine saw Randolph return that love by indulging in embarrassing public behaviour, including getting drunk and caving classified military maps in the car.

Except for their youngest daughter, Mary, all of the Churchill children's marriages failed. Clementine and Winston had given Mary a better start in life by leaving her upbringing almost entirely to Clementine's cousin. "Unlike the others she had not been left with a succession of unreliable nannies and governesses . . . her brother and sisters had not lived for long in any one place, whereas Mary had been spared the moves ... she had none of the problems of her sisters," says Hardwick.

Clementine's offspring apart, the true child in her life was Winston himself. The passing of years did not deter him from his gambling and a luxurious lifestyle, which he could ill afford.

"Her letters to her daughters show that she also regarded the real man she had to live with as a wilful, troublesome and often misguided, if highly talented child . . . He blamed his wife because painting gear was not as he wanted it, and then complained because he was loo tired to paint anyway.

One of Clementine's major difficulties in preserving Winston in his public, godlike bubble was that although in his 80s and in poor health, he continued as a public figure. He would not give up his MP seat even though his deafness was a real problem and he stubbornly refused to wear a hearing aid.

She continued to strive for her husband's untarnished image even after his death and was devastated when Winston's doctor wrote a book on his patient. "He had, she felt, robbed her husband of dignity by describing such occasions as the one when he clambered about in a plane wearing only his pink silk vest," comments Hardwick.

. Clementine Churchill The Private Life Of A Public Figure by Joan Hardwick will be published by John Murray on June 26th.