By Beth Hale

FOR a man of Alistair Stewart’s apparent wealth and status, the £5.6million asking price for a beachfront home in the Caribbean paradise of Turks & Caicos must have appeared a drop in the azure-coloured ocean.

The well-spoken, supremely dapper 53-year-old was apparently a retired Goldman Sachs billionaire. He ran his own hedge fund in Switzerland, travelled by private jet and checked in and out of five-star hotels as if to the manor born.

Little wonder then, that when he struck up negotiations with Nina Siegenthaler, the pretty blonde Turks & Caicos-based vice-president of Sotheby’s International Realty, to buy Hartling House, a 9,000-square foot villa on the island of Providenciales, she found him utterly plausible.

So plausible, in fact, that she not only fell in love with Stewart, but was persuaded to invest her £600,000 life savings with him.

Sadly for Miss Siegenthaler, just about the only genuine thing about Stewart was his name.

Far from being a billionaire ‘businessman’, he was in fact a Cambridge University dropout living on benefits in a housing association flat in the West Sussex town of Burgess Hill. There was no Swiss hedge fund, simply a company letterhead — Quantum Capital — that he attached to emails, fired off from the laptop in his living room.

Earlier this week, Stewart, who researched the lifestyles of the super-wealthy in meticulous detail to fuel his fantasies, was warned he faces jail after he appeared at London’s Old Bailey. He pleaded guilty to defrauding Miss Siegenthaler, a plea that encompassed a string of other acts of deception.

There will doubtless be many who will question just how an intelligent, professional woman could be duped by a man who has seemingly never held down a real job and whose only financial resources came from a small family inheritance — and, of course, the poor woman he was conning.

Certainly, this is something that brokenhearted Miss Siegenthaler, 37, has contemplated, as she attempts to rebuild her life and fortunes back in the tropical tax haven. ‘You never believe something like this could happen to you,’ she told the Mail this week. ‘It’s absolutely surreal. It is vital people realise the dangers that are out there. I hope this acts as a warning.’

So who is the real Alistair Stewart and just how did he manage to deceive so many people? For, as the Mail has learned this week, Miss Siegenthaler was far from Stewart’s only ‘mark’ — the word con-artists use to describe their victims.

A pilot, a yacht broker, an interior designer and a yacht captain and his wife all fell prey to Stewart’s elaborate two-year deception.

His first victim was an elderly widow whom he fleeced of her life savings.

STEWART was born into a life of privilege, growing up in an affluent corner of Surrey, where his father Hugh worked for a chemical manufacturer and his mother Sylvia was an anaesthetist. He was an academic highflyer and won a place at Cambridge, but later abandoned his studies.

Soon after this, in 1982, his father died. Quite what impact this loss had on Stewart is unclear. He inherited a small legacy after his mother died in 2007 and there is said to be ‘no love lost’ between him and his younger sister, Sandy, seemingly because of his criminal behaviour.

Unmarried and unable to hold down a job, Stewart immersed himself in the fantasy lifestyle to which he aspired — learning everything from the makes and models of different helicopters, to the costs of yachts of all shapes and sizes.

After moving into his Burgess Hill flat in the Nineties, he befriended his elderly next-door neighbour, Brenda Keys. By this time, Stewart had already been in jail for offences which included running up debts of £75,000 on a stolen credit card. Mrs Keys, 73, a widow who had bought up three sons alone, was an easy target.

She died in 2004, before Stewart was unmasked, unaware she had been conned. Today, her son Geoffrey, 54, a builder, explains how credit card statements found after his mother’s death revealed that Stewart ran up huge bills at her expense.

Stewart would later claim he borrowed the money from Mrs Keys, but Geoffrey says the fraudster plundered £27,000 of his mother’s money, which has never been recovered.

‘Alistair used to tell my mother he had everything,’ he says. ‘My brother had a Mercedes CLK and he claimed he had one, too. We thought it was strange that he once got in my brother’s car and didn’t know how to move the seats back.

‘ He also said he worked as a helicopter pilot to the rich and famous and owned a big house in Chelsea. He told my mother the flat in Burgess Hill was just a more convenient address for getting parcels delivered.’

Presumably afraid of being discovered, Stewart would disappear whenever one of her children visited.

‘I would walk into her flat and see two plates with roast dinners on or two glasses of wine and would ask where he was,’ says Geoffrey. ‘ She would always say, “Oh, he had to leave suddenly”. I know he saw me pulling up and would leave.’

To discover that the cream teas at Brighton’s Grand Hotel and days out their mother so enjoyed with Stewart were actually paid for with her savings and pension has been a bitter pill for the children to swallow. ‘I always knew something was wrong,’ says