The Queen’s finances should fall within the scope of an investigation into the Paradise Papers leak, Jeremy Corbyn has suggested.
The Labour leader indicated the monarch should apologise if her private estate invested £10 million of her personal fortune offshore to avoid paying tax in Britain.
The disclosure of 13.4 million previously-secret documents reportedly ties major companies and political figures to secretive overseas arrangements.
It includes claims that the Queen has £10 million of her personal fortune invested in an offshore tax haven.
There is no suggestion that those involved acted illegally.
Asked if the Queen should apologise for the offshore investments revealed in the papers, Mr Corbyn told the CBI’s annual conference in London: "Well anyone that is putting money into tax havens in order to avoid taxation in Britain, and obviously investigations have to take place, should do two things - not just apologise for it but also recognise what it does to our society.
"Because if the very wealthy person wants to avoid taxation in Britain and therefore put money into a tax haven somewhere, who loses? Schools, hospitals, housing, all those public services lose and the rest of the population have to pay to cover up the deficit created by that.
"And so I think with the Paradise Papers, which I have been reading through like all of us this morning, are quite shocking."
Later he told Bloomberg TV there should be "an inquiry into all the revelations about the Paradise Papers".
Asked if that included the Queen, Mr Corbyn replied: "Everybody. The Royal Household are subject to taxation. I don’t know what has happened in that case. These issues all must be part of that."
After Mr Corbyn’s comments, a spokesman for the Labour leader insisted he did not call for the Queen to apologise.
"Jeremy did not call for the Queen to apologise but said anyone who puts money into a tax haven to avoid paying tax should, and that they should recognise the damage done by avoidance to society," the spokesman said.
The Duchy of Lancaster, the private estate of the Queen, was found to have millions of pounds invested in offshore arrangements.
Around £10 million from the Queen’s private fund was paid into funds in the Cayman Islands and Bermuda between 2004 and 2005, according to reports.
A small part of the money was traced to a lender which has previously been criticised for ripping off poor customers.
The Queen voluntarily pays tax on any income she receives from the Duchy.
A spokesman for the estate said: "We operate a number of investments and a few of these are with overseas funds.
"All of our investments are fully audited and legitimate."
Political figures and celebrities are said to feature in the leaked papers, with stars of hit BBC comedy Mrs Brown’s Boys among the latest named.
Paddy Houlihan, who plays Dermot in the show, Fiona O’Carroll, who plays Maria and Martin Delany who stars as Trevor, made use of a scheme that used trusts based in Mauritius and a series of loans and consultancy payments to reduce the tax they paid in the UK and Ireland, the Guardian reported.
Also among those said to be named in the papers are former Tory treasurer Lord Ashcroft and US president Donald Trump’s commerce secretary, Wilbur Ross, who is reportedly linked to a Russian firm.
Mr Corbyn called for a public inquiry into tax avoidance to urgently restore public confidence in the tax system.
But Theresa May has refused to commit to a formal probe or to introducing a public register of who owns offshore companies and trusts in British tax havens, saying only that people should "pay the tax that is due".
Asked whether she would insist on an inquiry and public registers, the Prime Minister told the CBI: "We have seen more revenues coming to HMRC over the last few years - since 2010 £160 billion extra that they have been able to raise.
"But we do work, there’s already work that’s been done to ensure that we see greater transparency in our dependencies and British overseas territories and we continue to work with them.
"HMRC is already able to see more information about the ownership of shell companies, for example, so that they can ensure that people are paying their tax.
"We want people to pay the tax that is due."
Downing Street said Mrs May did not have any direct offshore investments and her assets were held in a blind trust, in line with normal practice for ministers.
"There is a well-established set of procedures and mechanisms," the Prime Minister’s official spokesman said.
Beyond the UK, the White House was hit by suggestions that it has ties to Russia.
Mr Ross is allegedly shown by the papers to have money in a shipping company which deals with Russian leader Vladimir Putin’s son-in-law.
But he told reporters during a trade visit to London it would be "incorrect" to characterise Navigator’s relationship with Sibur, a gas company co-owned by Kirill Shamalov, who is married to Mr Putin’s daughter, as a partnership of any kind.
Hundreds of individuals and companies reportedly have had their overseas investments exposed by the files, which are also said to reveal that major global companies have exploited offshore schemes to avoid tax.
First obtained by the German newspaper Suddeutsche Zeitung, the documents stem from two offshore service providers and company registries from 19 tax havens, the Guardian reports.
The International Consortium of Investigative Journalists oversaw the project.