The Liberal Democrats have been accused of hypocrisy after The Times discovered that the party’s biggest business donor is controlled by a company in an offshore tax haven.

Alpha Healthcare, a residential homes firm which gave the party £125,000 this year, is ultimately run by Harberry Investments in the British Virgin Islands.

This week the Lib Dem conference suggested a clampdown on the use of offshore companies as part of action on tax loopholes for the super-rich.

Chris Grayling, the Conservative spokesman on work and pensions, said yesterday: “By saying one thing and doing another, the Lib Dems will not just undermine confidence in their own party, but affect confidence in politics as a whole. In this case the Lib Dems are clearly guilty of double standards.”

Alpha Healthcare, based in Redditch, Worcestershire, runs ten care homes across Britain and had a turnover in 2006 of £14.5 million. The company has been a generous corporate backer of the Lib Dems, giving the party £100,000 last year, £160,000 in 2005 and £10,000 in 2004.

Alpha Healthcare’s ultimate parent company is Harberry Investments, which is based in Tropic Isle Building on the island of Tortola. Harberry’s turnover and tax payments remain hidden because the company is based in an offshore haven where businesses do not have to declare their accounts publicly.

Bhanu Choudhrie and his brother Dhruv are listed as shareholders in Harberry and are also directors in Alpha Healthcare, according to Companies House. They are Indian citizens and have “nondomicile” status, according to one colleague.

This means that they can, if they wish, avoid British tax on any income or gains from their overseas assets.

Bhanu Choudrie, 29, is registered as the owner of a £4.4 million flat in Cadogan Square, Chelsea. The charge of the flat is registered with HSBC in Jersey, another offshore haven.

He is co-director of the mobile phone company Hybyte Solutions and Services, which was fined by the industry watchdog for sending out hundreds of unwanted text “jokes” for £1.50 each.

Dhruv Choudrie, 32, has an apartment in a private road in Kensington. In 2004 he was reported to have fallen victim to a conman’s sting when he ordered a Ferrari 360 Spyder, paying a 10 per cent deposit. He forwarded more cash and ended up losing £84,000. Both men are unmarried and were said to be in India yesterday.

This year’s donation from Alpha Healthcare is the biggest received from a private business since the businessman Michael Brown gave £2.4 million through 5th Avenue Partners in 2005. Mr Brown, 41, is to appear in court this month in connection with an alleged multimillion-pound series of frauds and is also charged with perverting the course of justice and transferring criminal property.

The Electoral Commission is awaiting the end of any court cases against Mr Brown before deciding whether the Lib Dems should give up any of the money he gave them.

According to a resolution at the Lib Dems’ conference, the party wants to remove loopholes exploited by the rich and plans to bring gains made by nonresidents on property in Britain within capital gains tax.

The Lib Dems have described the situation as grossly unfair, saying that Gordon Brown has avoided the issue for fear of prompting an exodus of wealthy foreigners.

Vince Cable, the party’s Treasury spokesman, has promised to close the loophole that exempts nondomiciles from tax on their British homes. Under his proposals, they would also lose their status if they stayed in Britain beyond a few years.

“The rich and well-advised exploit loopholes and end up paying 10 per cent tax rather than 40 per cent. Nondomiciles taking advantage of offshore trusts avoid capital gains tax and people avoid stamp duty by registering their house as being owned by a company,” he said.

Government figures show that there were 112,000 nondomiciles in 2005, an increase of 74 per cent from three years before, and accountants believe that the figures are rising rapidly. The Treasury says that it does not know how much tax they are able to save on their overseas earnings each year.

A spokesman for Alpha Healthcare declined to comment.

Last night a spokeswoman for the Lib Dems said: “Liberal Democrats are not opposing in principle the status of nondomiciled investors but we do believe that the current tax exemptions should be tightened up.

“Our position was developed by the Tax Commission completely independently of the view of any particular individuals.”

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