The courage of Sarah Brown

A determined-looking woman unpacks her kit and begins her work-out. It's hard at first and her muscles ache but she carries on. Sarah Brown never gives up. Slowly, the fitness that once enabled the 38-year-old to work crazy hours as a driven PR consultant is returning. The shapely figure that turned the head of the Chancellor of the Exchequer is coming back.

It's almost five months since she lost her first baby, Jennifer Jane, who suffered a fatal brain haemorrhage. Now, say her friends: "She is coming out of her cocoon." The photographs of a luminous, confident woman looking drawn and hollow at the baby's funeral in Fife in January is etched in all our minds. The months that followed have been gruelling.

But Sarah Brown's will is famously strong. Determined not to be defeated by the agony of losing her first child, she has thrown herself back into her work as head of the international arts division with the Brunswick PR consultancy. Next month, she'll venture back on to the public stage for the first time. On 30 June, the Palace Theatre in Shaftesbury Avenue will be the venue for a glittering night of comedy in aid of the National Council for One Parent Families, with Ben Elton and Stephen Fry topping the bill.

But all eyes will be on Sarah, who, as patron of the appeal, is the driving force behind the event. As the child of a broken home herself, she has long been a supporter of lone parents - an unfashionable cause in New Labour these days. Next month's comedy extravaganza is the culmination of the Magic Million Appeal, which she has spearheaded to raise £1 million pounds for the charity.

Since 10-day-old Jennifer died at the Edinburgh Royal Infirmary, Sarah has made only a handful of public appearances. She has been seen from time to time with her husband at receptions, such as Peter Stothard's party to mark his birthday and departure from The Times in February. She dutifully poured the tea for her husband on the day of his triumphant Budget - an image strangely unsuited to a woman of cool, independent character, who can seem aloof until she lets her guard down. This time though, she's not the Chancellor's consort but a driven career woman with a cause to champion.

When she presented an award at the Daily Mirror's Pride of Britain ceremony in March, the paper's editor, Piers Morgan, who sat next to her at the event, said her determination not to give in to despair was clear. "She's a very gutsy woman,'' says Morgan. "I thought she coped very well, given how soon it was after Jennifer's death. It was obviously a devastating blow, but she has real courage.''

According to one friend, the last month has seen a dramatic improvement. "I spoke to her two months after Jennifer and, to be honest, it was pretty grim. Things are still not the same - how could they be? - but they are better." She has encouraged her famously industrious husband to bury himself in his work, and, say acquaintances, is delighted by both his fortitude and his present successes. But, says another confidante, she finds the Chancellor's trips abroad stressful. "She is not the type to traipse around behind her husband and doesn't go with him to summits. But she finds it very difficult now to be left behind on her own." The flat in Westminster - a workspace full of Gordon's books, papers and pamphlets - can be a lonely place when he is away.

The bereavement has brought the couple even closer together. Sarah is not a gushing person by nature, which has sometimes given the impression of her marriage as a partnership, but not a red-hot passion. But she has said that she "couldn't have got through it all" without Gordon and that the couple have shared their grief, rather than attempted to suppress it.

Even with her husband for support though, going out can be a trial. Once a habituè of the London media and advertising scene, frequently to be seen at fashionable members-only club Soho House, she has confided that she sometimes now finds going out unsettling. Still eye-catching, the 38-year-old has sometimes looked uncomfortable in public. She is happiest among old friends, where she can blend into the crowd.

Although she dresses smartly in neat jackets and TV-friendly colours when she is alongside the Chancellor, she prefers to wear more relaxed clothes - often long skirts, linen shirts and her one fashion indulgence, fine, colourful scarves - when she feels she is not "on show". As a result, she can often be at gatherings without attracting attention, and that is just the way she likes it.

At one political social evening, she told a fellow guest who offered to escort her out of the corner that one of the strangest aspects of grief was the discovery that you could only deal with one or two people at any given time, and that a throng of journalists and politicians suddenly seems intimidating.

Who has seen her through the hard times? Not the Prime Minister's wife, according to furious allies of the Chancellor. "Cherie still blanks her,'' says one. The relationship between the two women has always been cool. Mrs Blair is, if anything, more suspicious of the Chancellor's ambitions than is her husband, and believes that Sarah's PR skills are a significant factor in Mr Brown's bid for Number 10. When she and Cherie meet in Downing Street, barely a word is exchanged. Sarah was said to be cross to discover that Cherie had "popped in" to 11 Downing Street and mingled with guests at a recent reception, leaving some guests with the impression that she was host. Two driven women, who might otherwise find much in common, are divided by what Mrs Blair believes to be the over-weening ambition of Mr Brown and his wife.

No one doubts that Sarah has high ambitions for Gordon and that she sees herself as a part of his rise even further in politics. Her feminist friends were confounded when she announced that she would be taking his name on marriage and renouncing the maiden - and business - name of Macaulay. There was talk of a desire to strike a contrast with Cherie, who insists on being known as Booth in her professional life. The Blairs did not attend the wedding - a quiet affair in Scotland - although they did join mourners at the funeral. The real friends on whom she has leant in her grief are honoured in the introduction she has written for a selection of writings to be published in aid of the Magic Million Appeal.

In her preface to the volume she has co-edited, she thanks her brother, Sean - The Times film writer - her mother, Pauline, and Sue Nye, her husband's tough political secretary who has emerged as a particularly strong ally since Jennifer's death. A reported rift with Julia Hobsbawm, the co-founder of the PR agency, Hobsbawm Macaulay, over the circumstances in which Sarah left the company, appears to have healed. "I don't think it's appropriate for me to comment, given that Sarah is such a private person,'' says Hobsbawm. But mutual acquaintances insist that the two women, who have known each other since their days together at Camden High School for Girls, are talking frequently again. Jennifer's death put whatever differences these two ambitious women might have had into perspective: it was, say friends, Hobsbawm who took the initiative in the first days after the Browns' loss.

The bereavement also transformed a woman most of the public recognised only as the wife of the Chancellor into an instantly recognisable figure commanding profound sympathy. According to one aide to the Chancellor: "The letters, even from people they had never met, were a great help to Sarah." There were 14,000 such messages of condolence, and replying has been a form of therapy.

She has sent out cards showing a picture of Jennifer and bearing the dates of her short life. "She was a little person,'' she has said. Gordon's brother John spoke eloquently of Jennifer as a "little angel" in the funeral address. The only hint of irritation she has shown has been with people who suggest that the death of her daughter will seem less crushing if she has another child one day.

The sheer physical toll the Caesarean section and its aftermath took was initially underestimated. "She was quite ill," says a confidante. "It wasn't just the obvious emotional horror of losing Jennifer. It was very physical, too." But as she has regained her strength, she has rediscovered her zest for work.

Her charitable endeavours have become intertwined with her employment at Brunswick, where she works two or three days a week. One of her close colleagues, Helen Scott Lidgett, says: "Since Sarah returned to work in March our projects have been going fantastically well. We are a close team." Officially, Sarah is a consultant for its international arts division, but she will also oversee a growing commitment by the agency to charitable work and intends to set up a new organisation to help sick children and young teenagers to assist other charities in fund-raising and publishing.

The house-hunting on which she had embarked before the baby's birth has been put on hold. The Chancellor's home in Scotland has become home for Sarah in addition to the couple's roomy Westminster flat. When she and Gordon have people over to the constituency home in Dunfermline, and run out of seats, the allegedly dour Chancellor and his wife are happy to cuddle up on the floor. One Scottish Labour source says: "Sarah has made his notoriously messy house a real home. When you see the two of them together in Scotland where they relax, they're just a couple like any other."

Except they're not. Other than the Blairs, no political couple in Westminster is so scrutinised or burdened with expectation. One of Sarah's girlfriends grumbles: "She should be so careful what Treasury spin-doctors do with her. They try to play her off against Cherie. But the problem is that rather than having Sarah standing proudly next to Gordon and his red briefcase on Budget day, they turned her into a woman wearing a cardigan pouring her husband a cup of tea."

But Sarah, a veteran spin-doctor herself, knows the rules of the game. "She's not daft," says one longtime friend. Indeed, it was Mrs Brown, rather than the Chancellor's spokesmen, who let it be known last year that her husband was obsessed by the television programme Popstars. She also knows that her husband is the strong favourite to be the next Prime Minister and she wants to be there beside him all the way. A recent poll suggested that he is now more popular than Mr Blair. She is well aware of what might lie ahead and her return to public appearances is part of preparing for that.

"Sarah knows that Gordon could be Prime Minister one day and is trying to find a role for herself,'' says Piers Morgan. "She'll never forget her daughter, but she's determined not to let what happened with Jennifer ruin her life."