She was once a beauty queen but now she can afford all the tiaras she could ever want. Britain’s wealthiest woman in this year’s Rich List is a former Miss UK who went on to marry a bio-tech millionaire and write a number one hit for the All Saints’ pop group.

“You never know what will happen in life, said the mother of Kirsty Roper. “Nobody knows how they are going to end up.”

Her daughter Kirsty has gone from a middle-class childhood in a quiet Staffordshire village to a life of star-studded parties, chalets in Gstaad and racing yachts.

In The Sunday Times Rich List 2008, published today, Kirsty and her husband Ernesto Bertarelli are new entries, ranked sixth, with a fortune of £5.65 billion.

“No, it hasn’t changed her at all,” said Roper. Kirsty still regularly pops home to see her mother.

Though she and Ernesto are twice as rich as Sir Richard Branson, Kirsty remains little-known in Britain. She likes it that way, avoiding the limelight and rarely speaking in public.

“She is very happy being the mother of three lovely children,” said Roper. “She had a happy childhood and she wants the same for them. She’s a very hands-on mum.”

Brought up near Stone in Staffordshire, Kirsty enjoyed a comfortable childhood. Her father was a director of the pottery firm Churchill China and the family’s large home is set in immaculate gardens with a tennis court. She went first to a local private Catholic school, then Howell’s, a girls’ boarding school in Denbigh. Though she was reasonably academic, her real interest lay in singing. A life of mega-riches did not seem likely.

“She loved musicals. She’s a very good singer,” said Roper. Her dream was to carve out a career in music or modelling. She began working for her father while auditioning for modelling and singing roles.

One of her first commissions was having her feet photographed for a fashion catalogue. That might have been the height of her fame were it not for the intuition of her mother.

One day, after a local fashion show, Kirsty felt unwell with pains in her head and spine. She thought it was flu.

Her mother immediately called a doctor – who diagnosed acute meningitis, gave her a shot of antibiotics and dispatched her to hospital. Another hour’s delay, Kirsty was told later, and she would probably have died.

She recovered and blossomed. At just 17, she was catapulted onto a new plane by winning the Miss UK contest and then coming third in Miss World. But her life was really transformed when she met Bertarelli.

“She was living in London and they met through mutual friends,” recalls Roper. “I had no idea who he was. I knew nothing about him.”

Ernesto’s father had built up a pharmaceutical company, which his son took over. Ernesto rode the biotechnology boom of the 1990s, steering the firm to greater growth and playboying hard while he did so. Then he, too, changed course.

At a grand ceremony in Switzerland, he married Kirsty. “It was in a huge marquee, in the summer in the mountains near Gstaad,” said Roper. The couple, who now live in Geneva, soon began a family.

His other baby was a yachting syndicate, Alinghi, set up to mount a challenge for the greatest prize in sailing – the America’s Cup. Ernesto poured £80m or more into the project, even hiring star sailors from New Zealand, the defending holders of the cup, to win the trophy. Last year he retained the prize and is now embroiled in a legal battle over the staging of the next challenge.

Kirsty is also one of the organising forces behind the glitzy parties that enliven the America’s Cup. In Valencia last year a huge bash saw Duran Duran – fronted by keen sailor Simon Le Bon – entertain a crowd that included Naomi Campbell, Petra Nemcova and Spanish celebrities.

But is Kirsty really a sailing fan? “No, not really,” laughed her mother. “It’s a man thing, well at least the type of sailing that Ernesto does.” Kirsty wrote the number one Black Coffee about her husband in 2000. Its lyrics are a paean to a yachtsman: “Sail away, I miss you more/ Until you see the shore/ There I will be waiting, Anticipating.”

Girls on top

— Kirsty Bertarelli, pharmaceuticals £5,650m
— Lady Green, retailing £4,330m
— Charlene de Carvalho, inheritance, brewing, banking £3,630m
— Kirsten Rausing, inheritance and investments £3,500m
— Slavica Ecclestone, motor racing £2,400m
— Baronness Howard de Walden, property £1,600m
— Lady Grantchester, retailing and football pools £1,200m
— Hourieh Peramaa, property £1,000m
— Ruth Parasol, internet gambling £763m
— Ann Gloag, transport £720m

Figures show family and personal wealth