Bronwen, Lady Astor, who has died aged 87, was, as chatelaine of Cliveden in the early 1960s, a supporting player in the Profumo affair that came to be regarded as a turning point in 20th century Britain; a fashion model hailed as one of the great beauties of her day, she found herself ostracised in the wake of the scandal by many of the guests she had welcomed at her husband’s ancestral home.

She sought consolation in religion and, while repudiating the description “mystic”, admitted to various intense experiences of God. She went on to establish a charismatic religious community at her Godalming manor house and, when internal divisions caused it to collapse, to practise as a Christian psychotherapist and spiritual director.

Before her marriage, as Bronwen Pugh, she was the forerunner of modern supermodels. In the mid-1950s, she became muse to the couturier Pierre Balmain who, unable to pronounce her name, called her Bella and announced that she was one of the most beautiful women he had ever met, ranking her the equal of Elizabeth Taylor and Vivien Leigh.

He acclaimed her Garbo-esque quality, a combination of height (just under 6ft), her purposeful, haughty bearing and a certain disregard for conventional restraints, not to mention her aristocratic looks (though she was actually middle-class), piercing green-blue eyes and elegant sculpted face. Even in old age Bronwen Astor still turned heads, as she had in the 1950s when, after a spell as a BBC television presenter, she became the public face of the Balmain fashion house.

But being a model girl (she eschewed the word “model”, believing it carried tawdry overtones), was merely a distraction; while she worked by day with fashion designers, by night and at weekends she read widely on spirituality and psychology. “A career in the most material of worlds thrived while her mind was fixed on spiritual concerns,” noted her biographer Peter Stanford. “Perhaps that accounted for the distant look that Balmain recognised.”

Bronwen Pugh moved into Cliveden as Lady Astor in October 1960, as the third wife of Nancy Astor’s son and heir William, the 3rd Viscount Astor, known to his friends as Bill. Nancy Astor, a feisty Virginian who had been the first woman to take her seat in the House of Commons and who died in May 1964, was dismissive of her new daughter-in-law on account of her career on the catwalks, meting out the kind of treatment that she reserved for all the women who were bold enough to marry her five sons. Indeed, she delighted in making their lives a misery. She was especially cruel to the three women Bill chose in turn to succeed her as chatelaine of Cliveden, though she did once admit to her biographer Maurice Collis that Bronwen was “the best of the bunch”.

When Bill Astor died prematurely in 1966 (from a broken heart, it was said, the result of his public disgrace as a Profumo player), Cliveden was handed back to the National Trust, to which his father had left it in 1942.

At least one of the Astor trustees continued to believe ever after that it was Bronwen who had brought the osteopath, Stephen Ward, a central figure in the Profumo scandal, into Bill’s life, and caused his ruin. But the opposite was the case. Ward’s tenancy of a cottage on the Cliveden estate predated Bronwen’s arrival in Bill’s life by several years.

The suggestion was also made that Bronwen was “just another of Stephen’s girls”, trained to seduce and then marry wealthy, titled older men. It was a Ward protégé, Christine Keeler, whose simultaneous affairs with John Profumo, Secretary of State for War, and a Soviet military attaché, precipitated the whole scandal.

But Bronwen, in her modelling heyday, had studiously avoided Ward on the London social scene, after being warned of his activities; polite “model girls” had nothing to do with him. Her introduction to Bill Astor came via a mutual friend, the banker Patrick de Laszlo. Initially she was reluctant to accept his offer of marriage but was persuaded, she recalled, by a profound sense that God had pointed her in his direction.

And once she arrived at Cliveden, she ended the free access Ward and his entourage of young women had previously enjoyed to the social life and facilities of the house – though she was (disastrously, with hindsight) persuaded to allow him continuing use of the swimming pool, infamously the scene of the first act of the Profumo drama.

Janet Bronwen Alun Pugh was born on June 6 1930 in London, the third daughter of Alun Pugh, a Welsh barrister practising in London who later became a county court judge. Her ascetic nonconformist mother Kathleen disliked children, but Bronwen became a model pupil at St Christopher’s Church of England primary school, down the hill from the family home in Pilgrim’s Lane, Hampstead; aged four, a fall from a bike left her with a squint.

Her father having ordained a Welsh education, in 1939 Bronwen was packed off to Dr Williams’ School, Dolgellau, which was cold and damp, and where the standard prescription for most ailments was a good gargle of Dettol. Her older sister, Gwyneth, watched out for her there.

On leaving school, Bronwen trained at the Central School of Speech and Drama but, deemed too tall to be an actress, she became a drama teacher, earning her diploma in 1951.

The following year, after the death of her best friend Erica Pickard in an accident, Bronwen Pugh decided to risk all on pursuing what had been their shared pipe-dream – to become model girls. Although already aware of a solitary inner instinct which she nourished by studying the psychological writings of such gurus as Gurdjieff and the theology of Pierre Teilhard de Chardin, she almost fell into modelling as a career in 1952.

Her height nothwithstanding, she created an immediate impression with the distinctively feline way she walked, dragging a coat down a catwalk, as one critic noted, “as if she had just killed it and were taking it to her mate”. Her career prospered: she had the remnants of her childhood squint fixed, changed agents, appeared in Vogue and other magazines, and in 1954 starred in the annual show for the Queen Mother, arranged by top couturiers and organised by the socialite Lady Pamela Berry, wife of the then owner of The Daily Telegraph.

Later that year she joined the in-vision announcing team on BBC Television, eclipsing, at least in one reviewer’s opinion, her colleagues Sylvia Peters and Mary Malcolm with her “very ladylike” style. However Bronwen Pugh’s screen career ended after only nine months, when Sylvia Peters returned from maternity leave.

She revived her catwalk career in Rome in 1956 when she was photographed in the latest fashions from Fabiana and Simonetta and, despite her Celtic roots and voluptuous 35-23-36 figure, hailed as the epitome of an English rose. In Paris, Pierre Balmain hired her on the spot – proclaiming “You are my Garbo” – and made her name.

Having been rebuffed by a young Welsh psychiatrist called Michael Davys, Bronwen Pugh found herself courted by the recently-divorced Viscount Astor, a man 22 years her senior. In 1959 she had undergone a profound mystical experience, a direct and all-consuming revelation of the divine; recounting this to Astor, she was impressed by his reaction, but daunted at the prospect of running one of Britain’s greatest stately homes; nevertheless she accepted his proposal of marriage.

On her wedding day in 1960, she was besieged by a huge press pack, intrigued by the supermodel marrying one of the world’s richest men – and one old enough to be her father.

Bronwen Astor briefly met Ward and Christine Keeler at the Cliveden swimming pool on the fateful weekend in July 1961 when Keeler caught the eye of Jack Profumo, but, being pregnant with her first baby, Bronwen turned in for an early night.

The ensuing scandal destroyed her marriage: Bill Astor found himself labelled a seedy playboy, adulterer, fool and coward; in its wake, Bronwen was cut dead at parties and at race meetings, and she felt degraded by it. “It was like living a nightmare,” she recalled. “There was an awful silence.”

After Astor’s death in January 1966, and well-provided for in his will, she moved with her two young daughters to an 11th century manor house in Surrey and in 1970 converted to Catholicism. For four years she was at the centre of a charismatic Christian community at the house but its high-minded ecumenical ideals were not so easily put into practice and it ended unhappily. Later, having trained as a psychotherapist, she was appointed chairman of the Religious Experience Research Centre at Oxford University.

She spent a vivid old age in London, finally feeling she could return to the capital from self-imposed exile in the countryside after the Profumo scandal. She continued to windsurf and fish for salmon into her eighties and was a generous benefactor of many good causes. She even returned briefly to the catwalk in 2011 for the Vintage Festival, held in the grounds of Goodwood, home to her daughter Janet, who had married the Earl of March. However, her sense of injustice at the way she and her husband had been treated post-Profumo remained with her until the end.

Bronwen Astor is survived by her two daughters.

Bronwen, Lady Astor, born June 6 1930, died December 28 2017