Pushing through swathes of paparazzi she carried a well practised air of hauteur, refusing to acknowledge anyone who enquired as to her wellbeing.
Nothing unexpected about that, you might think. The television presenter is, after all, a staple presence on the capital’s party circuit, used to being subjected to the glare of the media and certainly not a woman to crumple in the face of rigorous speculation about her private life.
Is it all over? Trinny posing with Johnny
Yet for all her attempts at normality, the past seven days have been traumatic for Trinny.
Growing doubts about her marriage to former rock drummer turned financial adviser Johnny Elichaoff last week crystallised as full-blown reports that the two had split.
The pair have held a series of crisis meetings in a desperate bid to salvage their nine-year marriage. They face, it seems, an uphill struggle.
For The Mail on Sunday can reveal that the chasm between them has deepened to such an extent that it is all but unbridgeable – caused by a toxic combination of his deep-seated jealousy, her unwavering ambition and the drastically different ways they cope with the addictions that continue to blight both their lives.
Trinny, 44, has fought a well documented battle with alcoholism. She has not had a drink for 16 years, and attributes her abstinence to religiously attending her local branch of Alcoholics Anonymous.
Trinny posing at the Sex And The City world premiere
Her 49-year-old husband, meanwhile, is dealing with a dependence on prescription painkillers, for which he was treated two years ago. But Johnny is, his friends fear, throwing his wife into despair.
As one well placed source explains: "Trinny is totally into recovery and the process of recovering. She feels let down that Johnny can’t make the same inroads."
Also the source says after all her problems, Trinny hates to be near drinkers.
"She won’t set foot in a pub, but Johnny will, so they have been living almost separate lives, which has taken its toll on their marriage.
"She is channelling her addictive personality into furthering her career, while Johnny is more laid-back and thinks that there’s more to life than work, work, work."
Trinny, of course, fronted the BBC’s hugely successful fashion makeover show What Not To Wear from 2001 to 2005 with her best friend and business partner Susannah Constantine.
The pair – in a move that is, with hindsight, bitterly ironic – went on to host a marriage "counselling" show, Trinny & Susannah Undress, on ITV in 2006.
This month they stripped off in their show The Great British Body, also on ITV.
Both women boast privileged backgrounds. Trinny’s grandfather was the head of British Steel, Sir John Duncanson, and Susannah’s father was ex-Eton and Coldstream Guards.
They first met at a dinner party hosted by Susannah’s former boyfriend Viscount Linley in 1994 and wrote a newspaper fashion column together before landing their television contracts.
Their frank advice and no-holds-barred criticism attracted more than seven million viewers and their accompanying fashion books have sold in excess of 2.5million copies.
Revealing all: Trinny and Susannah on The Great British Body
Coupled with lucrative advertising contracts, the two women have become a bestselling brand, among the wealthiest and most successful celebrities in Britain.
But that is not enough for Trinny, who gave birth to Johnny’s daughter, Lyla, in 2003.
"Trinny wants to conquer America," adds the source.
"She’s proud of what she’s achieved and always wants more, while Susannah, like Johnny, is far more laid-back. Johnny’s not interested in a lot of the things Trinny’s obsessed with and sees her celebrity lifestyle as increasingly superficial.
"He’s bored when she’s off doing her own thing and he feels stuck out on a limb. She feels let down. She says that she can’t be both adults in their relationship."
It is fair to say that the tables have turned somewhat for the couple, who own a £2.2million terraced townhouse in West London, where there was no sign of either of them last week.
Back in 1982, it was Johnny who commanded the limelight, as a madcap rock drummer who toured the world supporting U2 and Siouxsie Sioux.
Nicknamed Johnny Too Bad, he played in a Seventies band called Stark Naked And The Car Thieves before defecting to the equally bizarrely named Baby And The Black Spots and then playing in guitarist Robert Fripp’s League Of Gentlemen.
His musical career was interrupted by a two-year spell in the Army in 1984, and he went on to help manage rock bands Tears For Fears and Fairground Attraction.
It was a long way from the rather dry world of taxes and insurance that he inhabits nowadays.
Many wonder if, deep down, he still hankers after being a performer as he watches his glamorous wife command centre stage.
Trinny was still on the cusp of stardom when they met, and reeling from her traumatic childhood, teens and drink-soaked 20s.
The youngest of six siblings, she is the daughter of a wealthy banker and was dispatched to boarding school at the age of six.
It was an institution she recalls as "cruel" and "sadistic", not least for the time she was forced to stand naked in the school corridor as a punishment for her involvement in a water fight.
By her early teens she suffered from severe acne. "It was hideous," she says.
"It affected my self-worth, everything. It was the bane of my life. I grew my hair long just so I could cover my face."
She was not prescribed effective medication until she was 29, so she self-medicated with alcohol instead, drinking in an attempt to numb her embarrassment.
"I did everything," she admits. "It became a real problem. I would drink and go mad."
Working as a secretary, she spiralled out of control, living beyond her means and racking up £26,000 of credit-card debts in her early 20s until, at 26, she hit rock-bottom.
"I’d had enough [of drinking]," she remembers. "I felt so low. There was an exact moment when I just knew I didn’t want to do it any more. I was out with two very good friends of mine, who are now dead. They both died of alcoholism.
"It was about 3am and I thought, 'I don’t want to do this. I have to stop.' I’d felt that before, a hundred times, but I woke up the next morning and I still didn’t want to do it. And that was the first time in ten years I’d had that strength of feeling."
She spent a year in rehab. "I never want to go back to where I was," she says. "A lot of people do go back, so I still feel a day at a time."
Being married to a fellow addict may in some ways provide a source of support. But it is also, it seems, antagonising Trinny’s honourable intentions.
Johnny – who has a son, Zak, from his first marriage – developed an addiction to prescription painkillers two years ago when he had 20 operations after breaking his leg in a motorbike accident.
He was treated in a Californian rehab clinic in October 2006, during which time Trinny caused concern by collapsing in the aisle on a flight from New York to London.
She dismissed the incident, claiming she had simply had an allergic reaction to a sleeping pill.
Some close to the couple, however, feared otherwise. "Part of the reason for her collapse was that she had recently spoken to Johnny," says a confidante. "She was worried about his addiction."
Tellingly, it had only been a month earlier that Trinny insinuated they were suffering strains in their marriage.
She admitted: "Johnny and I had to deal with a difficult stage. We have a 'business meeting' where we talk about our issues. It works for us. You have to keep talking to each other."
Theirs is certainly a bond that has weathered a number of storms, perhaps the worst being Trinny’s struggle to become pregnant.
Susannah – married to Danish entrepreneur Sten Bertelsen and the mother of their three children – fell into motherhood effortlessly.
But Trinny was diagnosed with blocked fallopian tubes and endured nine rounds of IVF and two miscarriages before she conceived.
She said at the time: "It is stressful having IVF. I’m a hormonal cow for a month, but luckily my husband is very patient."
When she finally became pregnant she spoke glowingly of Johnny. "I still feel a sexy woman, which is important," she said.
"Some husbands are very funny about their wives when they’re pregnant and go off them sexually, but my husband never puts me down. I’ll say, 'I hate my thick legs,' and he’ll say, 'Trinny, you can cover them – and your t*** look fab.' He always makes me feel great."
She added poignantly: "I probably won’t have another. I’ve tried to have another baby. I would love Lyla to have a sibling near her own age, but what will be will be."
However, those close to the couple say the situation has now changed and that it is Johnny who is pushing to become a father again.
"In spite of all their problems conceiving in the past, he is keen for another child," says one source. "He thinks it would help ground Trinny but her response is very much 'not now'."
Indeed, her social schedule is such that another baby would struggle for space in her life.
When she is not performing sartorial overhauls she is entrenched in a glamorous whirl of charity fundraising as a trustee of the Chemical Dependency Centre and a staunch supporter of the Lavender Trust at Breast Cancer Care.
Counting Elton John, Mick Jagger and Liz Hurley among her many friends, she is undoubtedly well connected.
"She really admires Liz and sees how her husband Arun lavishes diamonds and exotic holidays on her," says the source.
"She sometimes wants that a bit for herself but isn’t married to somebody who gives her that.
"She’s the one everybody recognises at parties and he’s pushed out of the way by people trying to get to her. He feels emasculated."
There is also the prickly issue of Trinny’s appearance. A self-confessed Botox user, she has shocked viewers in the past with her scrawny figure, but insists that, at 5ft 7in and a steady nine stone, she eats heartily.
Yet although not suffering from an eating disorder, she is evidently fanatical about her health and beauty regime.
"She is on a desperate quest to stay youthful and trim and she’s often in bed early in the evening as a result," says a source.
"Johnny finds that over the top and superficial."
For all her workaholic tendencies and neuroticism – fellow contestant Piers Morgan labelled Trinny a "banshee" after her spectacularly bossy behaviour on BBC’s Celebrity Apprentice last year – Johnny has always been her most ardent supporter.
He said of his wife before their most recent troubles: "Trinny comes across as cold and aloof, but in fact she is the kindest woman I have ever met. She has a heart of gold. The steeliness people see in her is really a cover for her chronic shyness, believe me."
There is no doubting Johnny and Trinny’s earnest desire to make their marriage work.
But their shared experience of addiction – and the toll that it takes whatever its form – is both a blessing and a curse. Addiction is selfish and so, sometimes, is the determination to sustain a recovery.
Ambition, too, can be an unforgiving quality, especially if it is not shared in equal measure by a spouse.
Last week, Trinny was once again wearing her wedding ring, something she has been neglecting to do in recent times.
Is this a sign of a desire for reconciliation with the man who, for all their troubles, she so clearly adores?
How long the ring will stay there is anybody’s guess.
