We know her as Nancy — the fiery Italian who captured the glacial heart of England’s football coach, the super-Swede Sven-Goran Eriksson. We have seen her on her way to parties with the rich and powerful wearing outfits that dazzle the eye and defy good taste.

She held her overly made-up head high when Ulrika Jonsson told the world that she had been simultaneously romanced by Sven. We think of her as both a Hello! heroine and as a Dolly Parton victim trapped in an endless episode of Footballers’ Wives. Betrayal, bad taste and big hair — thy name is Nancy Dell’Olio.

Then, just as we are starting to get used to Nancy and her ability to add to the gaudy gaiety of the nation, it seems that she has gone and reinvented herself. Yes, the queen of Eurotrash is dead — long live the new caring, sharing, campaigning Nancy.

For while some real celebrities such as Sadie Frost or J-Lo start small, flogging their own brands of clothes or perfume, Nancy has jumped straight in with her own pressure group for world peace. It’s called Truce International and is based on a simple idea: instead of making war, why don’t we put down our arms and play football? Nancy tells me: “If we all believe in peace, then we will have peace.”

Nancy and Sven, unlikely though it may seem, are styling themselves as the 21st century’s answer to another peace-loving couple. “I think it was fantastic for John and Yoko to use their popularity in that way and I’d be very proud to carry on,” she says in confident if clunky English with a sexy Italian lilt. “They did a good job of promoting peace. It would be fantastic for me and Sven to also do that as a couple.”

So where does that leave Sven? “When I first mentioned this idea to Sven he thought it was fantastic,” says an excited Nancy. He is now a patron of Truce International and together they appeared on a recent MTV special to share with the world their new project and visions of global peace. Significantly, the television programme was called All We Are Saying — a line from Lennon and Ono’s song Give Peace a Chance.

It is difficult to see Sven and Nancy as celebrity bohemians, but you get the impression that Nancy has never seen herself the way the rest of the world does.

The Nancy Dell’Olio story is a classic tale of the small town girl with a hunger for big city glamour. Born in New York, Nancy was raised in the poor Italian port town of Bisceglie. One of five children, she lived in a small flat above what passed for the local fashion store. She studied law at Rome University and after completing her education married a man at least 20 years older — Giancarlo Mazza, a handsome and wealthy lawyer.

The besotted Mazza, who had separated from his first wife 17 years earlier, helped his new bride to set up a successful international law practice specialising in property. Thanks to him she amassed an impressive collection of couture and contacts. But one contact, whom she met in May 1998, made more of an impression than most. Mazza was a shareholder in the football club Lazio in Rome, which was managed by Eriksson.

It was true love, says Nancy. That is not quite how her stepchildren see it. Chiara, 38, and her brothers Francesco, 36, and Daniele, 30, see Nancy as an ambitious, manipulative social climber who got her claws into their vulnerable dad and used him to make money and a name for herself.

I arrived at the Nancy ’n’ Sven front door expecting a house that was at least a little bit mockable.But that was shock number one.

You would expect them to live in a mansion with a pool and tennis courts — at least with their own mini-football pitch — in some exclusive part of Surrey. But they live, by the standards of the rich, in a modest house by railway tracks in the un-posh area of a very posh neighbourhood in north London.