The woman at the centre of one of the most intriguing spying scandals since the cold war rubbed shoulders with some of Britain's highest profile businessmen at glittering evenings in London nightclubs.

Anna Chapman, one of 10 suspected Russian spies charged in the US, was allegedly taken to parties at Annabel's nightclub attended by businessmen including the private equity billionaire Vincent Tchenguiz, and Philip Green, who owns some of the UK's largest retailers.

The emerging picture of the glossy social circles Chapman moved in during her time in Britain mirrors FBI suspicions that the Russian secret service wanted her to ingratiate herself with influential people in the west. She was, said one businessman who knew her, a "great networker".

Wayne Sharpe, 53, executive chairman and founder of Bartercard, a trading exchange firm, said he met Chapman, 28, a number of times during 2005 at social gatherings. He said she was then the personal assistant of Nicholas Camilleri, chief executive of the Mayfair-based hedge fund company Navigator Asset Management Advisers. "The business people [in attendance] were the highest lot – I'm talking about Philip Green and Vincent Tchenguiz. She was in that set well and truly by being at Nick's side until the wee hours of the morning," said Sharpe.

"She was one of many intelligent Russian women who worked with Nicholas. It was always hard to determine what she did in his business, but she was very intelligent, attractive, personable and very articulate in English. She certainly was a great networker. She constantly ingratiated herself with all of the high-end businessmen Nicholas introduced her to."

A spokesman for Tchenguiz said it was "almost certainly true" he had met Chapman. "Vincent and Nick know each other and both go to Annabel's every Thursday," he said. "If Chapman was with Nick, she would have been introduced. But it would have been a passing encounter – totally innocent."There is no suggestion that Chapman obtained any information from the businessmen she mixed with. It is understood Green seldom visits Annabel's and has no recollection of meeting her.

Speaking exclusively to the Guardian last night, Camilleri said he found it hard to picture the 23-year-old girl he employed as a PA in 2005 as a Russian spy.

"She was a 'green, wet behind the ears' type of girl," he said. "She came across as having none of those sorts of spying-type aspirations, so I can't see how she developed them later."

Camilleri said that although Chapman was married when she worked for him, she never spoke of her husband and he never met him. "She was just an ordinary girl. She had nothing of any consequence about her. She was quite a quiet person."

He said that he did not introduce Chapman to Green, but added: "I go out every single night of the week and had many PAs before, during and after her. How could I remember who I took where and when?"

Barclays Bank confirmed yesterday Chapman had worked in its London office before moving to the US. Earlier, the British private plane hire firm, NetJets Europe, said that she worked for it in the UK, but not for as long as the CV claimed, or at such a senior level. Chapman's extensive online presence, including more than 90 photographs posted to Facebook and an apparently glamorous lifestyle as a property millionaire, has made her the focus of much of the media coverage of the case.

But quite what was her part in the spying network is a mystery. Inquiries in the US have established she was arrested after she herself had gone to a New York police station after a meeting with a supposed Russian agent who wanted her to pass on a false passport. In fact the Russian had been a US undercover investigator. While Chapman agreed to the task, when asked if she was willing to step up her spy work, she then failed to turn up to the set-up meeting. Instead she went to the First Precinct station in New York and told police that the passport had been forced upon her. It was only then that she was arrested by the federal authorities.

The manner of her arrest has been seized on by her lawyer, Robert M Baum, as evidence she was not the super spy the prosecution claims. "The government's case is very thin against Ms Chapman. There is no allegation she ever met face to face with any government official; and no allegation despite constant surveillance that she ever delivered anything to anyone or received any money," Baum told ABC News.

Several thousand miles away in Moscow, a few more pieces of the jigsaw of Chapman's life were emerging.

She grew up in the southern town of Volgograd (formerly Stalingrad) and came from an influential diplomatic family. She studied in Volgograd's middle school – where she was known as Anya Kuschenko – and lived with her grandmother when her parents decamped to Moscow.

Her father became Russia's ambassador to Kenya when she was in the 8th grade, friends said. "I'm certain this is all some kind of set-up," one friend told news portal lifenews.ru. "Even if you suppose she had become an intelligence agent, she would never have allowed herself to fail in this way. She was such a clever girl."

Another classmate, Tatyana Shumilina, recalled her as a "party animal" who introduced the other teenage girls to "decent music" including Metallica and Nirvana. She was usually dressed in ripped jeans, black T-shirts and had a punk style. "She was an excellent student. The boys liked her. You only had to see her once to realise she was very pretty. As she got older she got even prettier. She made no effort to hide her diplomatic connections – everyone knew her father was an ambassador in an African country."

After school she moved to Moscow, and studied at the People's Friendship University of Russia, one of the top Soviet-founded schools. After graduating in 2004 she went into business, initially for Fortis Investments. She set up her own online real estate business – apparently conceived from her experience of moving flats across Moscow.

Lifenews.ru says she married an Englishman, and moved to Britain, returning to Russia from time to time. Friends are unable to confirm this. "I don't know about her personal life," said Dmitry Porochkin, who met Chapman at a function of Moscow's young entrepreneurs' club. By this point she had dumped her Russian surname and was using the name Chapman, he told the Guardian. "She was an extremely talented businesswoman who specialised in start-ups," he said. "She was a genuine entrepreneur. She showed no interest in politics. She was someone who wanted to achieve her business targets, and said she planned to start an investment project in New York. How she ended up in the view of the US special services is a mystery."

Chapman's online real estate business www.domdot.ru was yesterday still up and running. Nobody answered the phone at its Moscow office. The portal offers a property search in 90 different regions of Russia and was highly successful, Porochkin said.

Chapman had intended to launch a similar online version in New York. She had also worked in banking in London, and for a hedge fund, Russian reports claimed. Other friends suggested that after frequent business trips she had moved to New York permanently only last year – camping out temporarily with her sister.