One lucky little lady

At just three weeks old, Iris Annabel Goldsmith is too young to appreciate the fuss her birth has caused. She is the first child of 23-year-old Ben Goldsmith and his 21-year-old wife Kate Rothschild, and therefore heiress to two of London society's most distinguished bloodlines and a joint fortune estimated to be well in excess of £300 million.

But, fresh out of her hospital swaddling clothes, Iris is living something of a gipsy lifestyle. While their three Chelsea townhouses are being knocked into one, Ben and Kate are "camping" with their new baby at the palatial Richmond home of Ben's mother, Lady Annabel Goldsmith, from whom Iris takes her middle name.

"We are moving in for six weeks because our house isn't ready," says Ben ruefully, adding that, fortunately, "Iris is a complete angel."

In suitably grand Goldsmith fashion, Ben has hired an old-fashioned maternity nurse to help with the baby, but Lady Annabel is pitching in with the organic babyfoods and biodegradable nappies that reflect both families' environmental concerns. "It's sheer heaven," she said. "I'm a very happy granny."

We meet in the Fulham offices of Babylist, the upmarket advisory service for parents with an environmental conscience and the largest supplier in Britain of organic baby products. Kate has agreed to promote a range of organic clothing and linen the company is launching on Monday.

Both she and Ben are vocal about their organic concerns. He leaps all over the place like an over-active labrador, firing off World Health Organisation statistics at breakneck speed. He points out that his uncle Teddy founded The Ecologist magazine, which his brother now co-edits, and that his father, Sir James, did a moral U-turn after amassing his industrial fortune and began to support traditional farming methods.

Ben and Kate married near her family home, Rushbrooke Hall in Suffolk, last September, three years after they were introduced at a dinner party and just four months after Kate discovered she was pregnant. The sumptuous wedding was seen as the union of two people linked not only by wealth, privilege and good looks, but also by strongly held ethical beliefs, concerns for the world and a shared experience of parental loss.

Ben, educated at Eton and once voted Tatler's most eligible bachelor, is the son of the late billionaire industrialist and founder of the Referendum Party Sir James Goldsmith, who died of cancer in 1997, and who had always wanted one of his descendants to marry a Rothschild.

Kate's mother is brewing and banking heiress Anita Guinness, but her father Amschel Rothschild was found hanged in a Paris hotel room in 1996, at the age of 41. His death was blamed on the burden of his immense inheritance and the pressure of being expected to take over the English branch of his family bank.

On their wedding day, Kate was given away by her brother James, while Ben's brother Zac was best man. Sundry Rothschilds, a brace of Parker Bowleses and Ben's sister Jemima and her husband Imran Khan were among the 600 guests.

Although Kate admits the pregnancy that spurred their early marriage was a happy accident - "it all happened so fast" - they were following family tradition in marrying young.

Sir James Goldsmith eloped to Gretna Green at the age of 21 with his pregnant mistress, the Bolivian tin heiress Isobel Patino (she died four months later in childbirth). Ben's sister Jemima married at 21, his brother Zac at 23.

"Fifty years ago everyone was getting married at this stage," says Kate. "Nowadays women want a career and then find it a shame when they have to give it up to have a family. If you have children young, you can have a career afterwards."

It seems almost absurd to hear a couple this wealthy talk about having to give anything up, or even having to work. Ben inherited £10 million "spending money" from his father's £1.2 billion will, lives off a £1 million-a-year allowance, and works as a venture capitalist in the City.

Kate is reported to be worth several hundred million pounds, and, before she became pregnant, filled up her spare hours working with fashion designer Patsy Puttnam, daughter of Lord Puttnam, making "one-off specialist pieces" (she was educated at Bryanston in Dorset, but did not go to university).

Anyone without a spare couple of million in the bank might be forgiven for writing them off as smug rich kids. Seeing them together, however - Ben in City pinstripes and Kate in a hippy smock and trainers, a small green star tattoo glimpsed beneath her wrist - one can't help but warm to the affection they clearly share, and to their genuineness.

You begin to worry that Kate is rather overwhelmed by her husband's exuberant personality. But, when he runs out of steam, she manages to get some wellchosen words of her own in. Her mother, she explains, lives on an organic farm in Suffolk and "was a big crusader in organic farming before Dad died. She has planted clover to get nitrogen back in the soil". Kate laughs, charmingly. "I do get most of my information from Ecologist editorials," she admits, "but it is vital to know all this. You've got to live a normal life but there are steps we can all take to help both the countryside and our health."

Surely, it's easy for her to say this, with all that money in the bank? "The fact is that people from the poorest to the richest are spending huge amounts more on cars and holidays but are spending less on food, which is the most important thing."

Motherhood has clearly further strengthened the couple's ethical attitudes, Kate's especially. "When you are pregnant, you become really conscious," she says firmly. "Babylist was beginning to get into the organic range but it knew how important it was to me that public interest in all things organic is boosted.

"Now 50 per cent of clients are asking for organic products. Today, 75 per cent of ready-made baby food is organic, yet mothers don't put their babies in organic sheets or on natural mattresses, which is just as important."

She warms to her theme. "Non-organic cotton is sprayed regularly with huge amounts of pesticides, mostly organo-phosphates, which do terrible harm to the environment, to wildlife and, most importantly, to people's health. It has been shown that the farmers in sub-Saharan Africa, who grow much of the cotton and are exposed to these pesticides, suffer health problems.

"Who knows what effects they could have if they were absorbed into the blood of a newborn baby whose skin is seven times thinner than an adult's?"

When I ask how Ben and his young wife manage to dine out ethically night after night - which he points out they do much less of now that Iris has arrived - he tells me that the Ritz was the first restaurant in London to be fully certified as organic, and that other upmarket hangouts like Annabel's (named, of course, after his mother), Aspinall's and Harry's Bar are following suit.

For the foreseeable future, Kate explains, little Iris Annabel Goldsmith will be wearing Moltex nappies, the only disposable and biodegradable brand in Europe. "In the UK alone, 2.9 million disposable nappies are used every year, which means a staggering 700,000 tonnes of waste," she explains.

Her husband nods soberly. Ideally, they agree, Ben would give up his job in the City and they would move out of that soon-to-be-completed three-in-one Chelsea townhouse and buy a large farm in the country, there to live a self-sufficient life. The Seventies sitcom The Good Life is, they say, their favourite TV programme.

I can't quite see this supremely selfconfident couple snuggling into Surbiton next to the Margo Leadbetters of this world. But I can easily imagine them a few years hence, still young and in love, tilling organic soil on some sprawling estate, surrounded by animals and children.

I ask Ben if his father would have approved of Kate's green credentials. He smiles adoringly at his wife and says: "He would have approved of Kate full stop."