LONDON (Bloomberg) - In yet another sign that financial centres are losing each other's confidence, Geneva bankers are insisting that Gordon Brown, the champion of deregulated markets in London and the British Isles, favours tax cheats at least as much as he says they do.

The British Prime Minister is calling for curbs on tax evasion and bank secrecy ahead of next week's Group of 20 summit at the ExCel conference centre in the docks near Canary Wharf.

"How much safer would everybody's savings be if the whole world finally came together to outlaw shadow banking systems and offshore tax havens?" Brown asked in a March 4 speech to US Congress on a visit to Washington.

While financial services in places like Switzerland are under scrutiny, Britain has a network of semi-autonomous financial centres with little or no taxes. That puts Brown in no position to campaign on tax and secrecy, said Pierre Mirabaud, chairman of the Swiss Bankers Association in Geneva.

"I would define Mr. Brown and the British government's position as full of hypocrisy," Mr. Mirabaud, who's also senior partner of Mirabaud & Cie, a 200-year-old private bank in the Swiss city, said in an interview. "At the end of the day, we are engaged in an economic war for market share."

Guernsey's private equity firms, Jersey's securitisation vehicles, the Cayman Islands' hedge funds, Bermuda's insurers, and the British Virgin Islands' holding companies are all incorporated on sovereign British ground.

The UK, the Channel Islands, the Isle of Man and Dublin held a combined 24 percent of offshore private banking assets in 2007, or $1.7 trillion, second after Switzerland's 27 percent share, or $2 trillion, according to Boston Consulting Group.

US President Barack Obama and German Chancellor Angela Merkel will be among leaders at the G-20 summit. Brown wants to reach an agreement on new global rules for tax havens, including the British islands. "These dependent territories have got to meet our standards," Brown told the UK Parliament on March 23.

Michael Ellam, Brown's spokesman, said the government is conducting a "serious and constructive" review of British tax havens.

Brown welcomed Switzerland's decision on March 13 to renegotiate international tax agreements by saying the move may mark "the beginning of the end of tax havens."

Bankers in Geneva say Brown, 58, should focus on his home market, rather than on Switzerland. They also question whether their country, which is outside the G-20, will be treated fairly.

"Gordon Brown must know much more about tax havens than we do because he's got a lot of tax havens around Britain," said Michel Derobert, secretary general of the Swiss Private Bankers Association, a Geneva group for bankers who cater to millionaires. "I'm not sure that G-20 is going to be as tough with its own members as they are with the countries outside the room."

Economy Minister Doris Leuthard is also concerned the Swiss financial industry, which accounts for about 12 percent of the country's gross domestic product, will suffer a disadvantage.

"If we're making concessions in administrative assistance, countries like the UK and the US have to follow," she said in a March 20 interview with Swiss newspaper Aargauer Zeitung. "We won't accept hypocrisy from other nations."

Non-profit organisations and labour unions in the UK have long criticized the country's offshore financial centers. The Trades Union Congress in London estimates tax havens cost the country £4 billion ($5.9 billion) of lost taxes each year.

"They undermine regulation and they enable secrecy on a massive scale," said John Christensen, director of Tax Justice Network and a former adviser to Jersey. "At this stage, we don't see the substance behind Gordon Brown's rhetoric."

Michael Foot, a former official at the Bank of England and the Central Bank of the Bahamas, is leading the UK review of nine financial centres. Mr. Foot, who cannot challenge the islands' freedom to set tax rates, said he will publish an interim report by April 22.

Politicians on Britain's offshore centers said they channel billions of pounds into London's financial district.

"We are vitally important feeders into the United Kingdom," Allan Bell, the Isle of Man's finance minister, said in a January interview.

Jersey, located off France's northern coast, is home to Granite Finance Trustees Ltd., through which UK mortgage lender Northern Rock plc. parcelled home loans and sold notes to investors before the bank was nationalised. A unit of New York's KKR & Co. is among private equity funds incorporated on Guernsey, an adjacent island in the Channel.

Cayman had 9,870 funds as of December. It is also home to Ugland House, where 18,857 shell companies were registered as of last year. Bermuda had 1,481 insurers as of 2007. In 2003, British lawmakers criticised the Inland Revenue, the country's tax collector, for selling government buildings to a Bermuda company that paid no UK tax.

Playtech Ltd., which develops online gambling software and has shares that trade on London's Alternative Investment Market, is incorporated in the British Virgin Islands and has its headquarters on the Isle of Man. Playtech paid a tax rate last year of 1.8 percent, or 762,000 euros ($1 million), said Shuki Barak, Playtech's chief financial officer.

The British tax havens create trusts that hide the identities of beneficiaries, Mr. Mirabaud said.

"I would only believe Mr. Brown is serious about addressing the question of transparency in offshore banking if he forces the real beneficial owners of any trust to be identified in all jurisdictions," Mr. Mirabaud said.

Geoff Cook, chief executive officer of Jersey Finance Ltd., which represents the island's finance industry, said there is not a register of trusts on the island, though trust management companies must know who the beneficiaries are.