THE political career of Prime Minister David Cameron was on a knife edge last night after he finally admitted that he made a killing from his late Scottish father’s tax-avoiding offshore fund.

After days of denial and stonewalling, including saying it was a “private matter”, Cameron told ITV’s Robert Peston that he had made a profit from selling his shares in the Blairmore Holdings concern run by his father Ian Cameron – a client of Panama firm Mossack and Fonseca – that never once paid tax in Britain in 30 years as it was registered in the Bahamas.

Within minutes of his admission, calls were being made on social media for Cameron to resign, some citing “hypocrisy” while one tweet said he was the “Wolf of Downing Street”. Labour MP and Commons Treasury select committee member John Mann was the first politician to call for his resignation.

The timing of the sale will hugely embarrass Cameron because he sold it just four months before he became Prime Minister – had he not done so, the shareholding would have had to be listed on his minister’s register of interests.

Indeed, last night there were questions as to whether the shareholding should have been registered at Westminster in any case as it was “overseas’” Furthermore, Cameron sold his shareholding just before it became liable for capital gains tax. Downing Street admitted that the stake was purchased for £12,497 in April, 1997 and was sold in January, 2010 for £31,500, giving the Camerons a £19,003 profit, just £300 below the capital gains tax allowance.

Heaping further embarrassment on the embattled Prime Minister, the Financial Times yesterday morning reported that Cameron, whose father was a serial user of offshore facilities such as trusts, had asked the European Council President Herman Van Rompuy in 2013 to differentiate between shell companies and trust funds.

He wrote: “I know some want Europe to go even further to prevent the abuse of trusts and related private legal agreements. It is clearly important we recognise the important differences between companies and trusts.

“This means that the solution for addressing the potential misuse of companies – such as central public registries – may well not be appropriate generally.”

Judith Sargentini, a Dutch MEP who led the European parliament’s work on the draft law, told the FT that the UK’s argument against a crackdown on trusts was that it would be an invasion of privacy – and that trusts have a special role in Britain in helping families manage issues around inheritance.

“I saw it [the British position] as a danger and a possible loophole,” Sargentini said. “Some member states saw it as an underhand way for the UK to get an advantage.” A Government spokesman said yesterday that the Prime Minister was concerned that pursuing trusts would detract from other aims he felt were more important. They added: “In the subsequent negotiations, we were able to secure a sensible way forward which ensures that trusts which generate tax consequences have to report their ownership to HMRC.”

But all that bluster was before the astounding revelation by Cameron that he had indeed benefited from his father’s offshore operations – a question that this newspaper and others including Labour leader Jeremy Corbyn had put to him earlier in the week, only for the question to be ignored.

Having the offshore holding was not illegal, but the Prime Minister also inherited £300,000 directly in his father’s will, before he made the global fight against tax avoidance his special mission.

He said on ITV: “I want to be as clear as I can about the past, about the present, about the future, because, frankly, I don’t have anything to hide, I’m proud of my dad and what he did and the business he established and all the rest of it.

“I can’t bear to see his name being dragged through the mud. I chose to take a different path from my father, grandfather and great-grandfather, who were all stockbrokers, and I’ve got nothing to hide in my arrangements and I’m very happy to answer questions about it.”

He rejected suggestions that the fund was created to shelter investors from tax, saying: “I think a lot of the criticisms are based on a fundamental misconception, which is that Blairmore Investment, a unit trust, was set up with the idea of avoiding tax. It wasn’t.

“It was set up after exchange controls went so that people who wanted to invest in dollar denominated shares and companies could do so.”

The global implications of the Panama Papers continue to emerge. The leaks were dismissed yesterday by Russian President Vladimir Putin, whose friends and associates are named in the Papers, as a plot to make Russia “more docile” and to cause “distrust within society toward the authorities, the state administration bodies, and to set one against the other”.

In Argentina, the country’s President Mauricio Macri is now under investigation by a federal prosecutor, Federico Delgado, after he too was named in the Panama Papers as director of an offshore company in the Bahamas.

In Iceland, Sigurour Ingi Johannsson, the agriculture and fisheries minister, was named as the new Prime Minister to replace Sigmundur David Gunnlaugsson, who stepped down following revelations in the Papers about his offshore interests.

Gunnlaugsson was the first politician to step down over his involvement with offshore funds. Last night in Britain, it became clear that he may not be the last.