The firm where Philip May works has paid no UK corporation tax in eight years, despite turning over nearly half a billion pounds.
The PM ’s husband is a client relationship manager at investment firm Capital International Ltd, which has turned over £467million since 2009.
But it recorded losses of £125million over the same period, making it ineligible to pay UK corporation tax.
Despite running a loss-making company for six of those eight years, CIL paid its board of directors a total of £43million in wages and other benefits over the same time frame.
Labour MP John Mann said: “It is fundamentally un-British to avoid tax. The Prime Minister should raise this at the breakfast table immediately.”
Finance expert Prem Sikka added: “It’s very odd a business can pay substantial amounts to directors while not turning a profit.”
CIL made profits of between £4million and £5million over the past two years, but continues to pay no corporation tax due to previous losses.
It made the losses after multi-million pound payments with other firms in the Capital Group, whose HQ is in the US. One subsidiary, Capital International Sarl, is based in tax haven Switzerland.
Capital blamed the impact of the credit crunch on profits and said CIL would begin paying UK corporation tax again next year, after a 10-year break.
But Professor Sikka, accounting expert at the University of Sheffield, said: “You might not make a profit every year, but if you’re not making profits over a long period, that should ring alarm bells. HMRC should investigate.”
Capital Group said: “Like other UK businesses, Capital International Limited does not pay corporation tax in years where losses are incurred or in profitable years where prior losses are carried forward.
“CIL will resume corporation tax in 2018.”
It is not known how much Mr May earns at CIL. The PM, pictured at church yesterday in her Maidenhead constituency, is not required to declare his income.
Capital Group has said: “Philip is not involved with our investment research or portfolio management activities.”
Last year it was reported Capital had invested billions in Amazon and Starbucks – firms accused of tax avoidance, which both deny. Mrs May has said: “It doesn’t matter to me whether you’re Amazon, Google or Starbucks… you have a responsibility to pay your taxes.” No10 declined to comment on Capital’s tax affairs.
A spokesman added: “Neither the PM or Philip May have direct offshore investments… everything has been declared.”
It comes as Capital was named in the Paradise Papers as using two of its funds in the Cayman Islands, a notorious tax haven, to invest in a Bermuda firm, another tax haven. CIL made 85% of its revenue last year in fees from Capital Group firms. The group is registered in US tax haven Delaware.