With an apparently insatiable desire for jewels and a refined eye for fine art and furniture, Shahra Christina Sylvia Marsh de Savigny was a familiar bidder at Europe’s leading auctions. But for six years the glamorous woman who posed as a French/Iranian heiress manipulated a system of trust used by auctioneers and exclusive stores to swindle them out of at least £2 million.

The woman known as Madame de Savigny was actually Shahra Marsh, a 52-year-old divorcée living on incapacity benefit. Police believe that she built up a huge collection of jewellery, paintings, silver, designer clothes and antique furniture as a “retirement fund”.

Yesterday, halfway through her trial at Southwark Crown Court, she pleaded guilty to the final series of 38 charges of fraud, obtaining property by deception and concealing criminal property from auction houses. She is expected to be sent to jail today.

After her marriage ended Marsh began to pass herself off as a member of European high society. She dressed the part, spoke fluent French and had an expert knowledge of antiques. And despite claiming incapacity and council tax benefit, she had four luxury apartments around London.

Between 2001 and last year Marsh used numerous aliases and addresses to carry out dozens of swindles. Her victims included Christie’s and Sotheby’s in London and Beaussant Lefèvre in Paris. In one audacious operation, she swindled the Parisian auctioneers Tajan of paintings, sculptures and jewellery worth £114,000 during four sales held in 2005.

She scoured auction catalogues and store brochures to identify possible targets before calling or writing a letter expressing interest in a possible item. She would then make daily personal visits to ingratiate herself with staff. Wearing the diamonds and clothes already conned from other stores, she was able to build up trust with senior sales staff and auctioneers.

She managed to convince shops and auction houses of her wealth by paying a cheque into her own bank account. This would appear briefly as a credit on her statement, but before it bounced she would tell her victims that she needed to have her purchases delivered urgently.

Assistants in jewellery shops were told that she needed the items to wear at a high society event the next day. If they insisted that she wait until the cheque had cleared, she would cancel her order. On one occasion a member of staff from the Giafferi auction house in Paris travelled by Eurostar to London to deliver a case of diamond and emerald jewellery.

She avoided paying £25,000 in rent on her London flats by telling landlords the same elaborate stories that she told the auction houses and shops.

Detective Constable Marek Coghill, from the Regional Asset Recovery Team, said: “She would drop names and utilise connections she had made in the jewellery world to provide the illusion that she was a trustworthy client, so she could eventually circumvent the normal strict practices.

“She wanted them to think a cheque from her was as good as cash. Very wealthy people don’t like to be questioned about whether they can support a cheque. It is a world that largely has to act on trust and she knows how to exploit that trust.”

When police tracked her down finally, they found her home filled with antique furniture, mirrors, statues and silverware. Detectives also found a key that she insisted was for the gate to her garden shed. It turned out to be for a safety deposit box that contained jewellery worth £770,000.

Months later they found a lockup storeroom that Marsh rented in East London. It contained furniture, jewellery, fur coats, shoes and 16th-century paintings.

Marsh, who received an income from a family trust fund, had fled Iran in 1978 and was educated in Paris before moving to London. She was arrested finally in April last year.

While on bail she continued to commit frauds until she was remanded in custody in September last year. Even in jail she continued. She wrote to a storage company saying that she would not be able to visit them as she was travelling for several months.

Detective Inspector Ella Marriott said: “We may never know how much she has taken. This is her pension fund. She is extremely deceiving and skilful in her endeavours.”

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