Andrew Wesbecher moved to London from New York in 2006 to sell software to banks and hedge funds. Last month he joined the exodus of American expatriates fleeing high taxes and the city's shrinking financial industry.

"I'm the last guy to leave that I know," said Wesbecher, 29, who worked for Tibco Software and lived in Notting Hill. "We are all packing up."

The number of US citizens in Britain fell 3.8 per cent to 126,000 in the 12 months to this month, says the Office for National Statistics. This year the Confederation of British Industry is estimating Britain's financial industry will lose about 45,000 jobs in the first nine months. Americans are heading home as Britain plans a 50 per cent tax rate for those who earn more than £150,000 (NZ$356,000) a year.

"Expats feel the tone has changed; it's less welcoming," says Mark Tilden, a consultant at CRA International who wrote a report for the City of London last year on the impact of taxation on corporate relocation decisions. "London's ability to attract talent has gone down."

Schools catering to international students report a drop in enrolment for the first time in seven years, and relocation companies say they are moving fewer people to Britain.

Janet Sherbow lives in Chelsea with her husband, Nikos Mourkogiannis, the former chief executive at the European arm of Massachusetts-based management consulting firm Monitor Co. The family plans to move to Greece after their daughter finishes high school next year.

"We are fed up with all the stealth taxes ... and now the 50 per cent tax rate," Sherbow says. "Six American families have moved from my street in the last six months."

Huddling under an umbrella, Wesbecher says he is no longer willing to put up with the frustrations of life in London after his commissions dropped and Tibco eliminated his expatriate benefits, cutting his take-home pay by 75 per cent.

"This is what passes for summer in London," he says. "The quality of life is a lot harder. Things are more expensive and the houses are smaller. "

Wesbecher isn't convinced the boom times will return: "The ethos of the ambitious, high-earning American is 'I will do anything to make money, even if it means moving my family'.

"When the performance bonuses go away, the value of being in this country goes away."