Billionaire says his affection for UK prompted decision, and leaving EU would leave it weaker

The Hungarian-American billionaire George Soros has said he is proud to have given £400,000 to an anti-Brexit campaign, saying it was his affection for the UK that prompted his decision.

Soros, a former refugee from communist Hungary who made $1bn (£720m) as a currency speculator betting against sterling on Black Wednesday, said leaving the EU was a tragic mistake which would weaken Britain.

The investor has come under sustained attack since details of his donations to Best for Britain were revealed last week.

Soros, who has given much of his personal fortune to his human rights organisation, the Open Society Foundations (OSF), said he had received “toxic personal criticism”. Some have said the language echoes the antisemitic attacks against him made by some governments, such as Hungary and Russia.

Writing in the Mail on Sunday, he said Best for Britain had his wholehearted support and that he had made no secret of his opposition to Brexit.

Profile Who is George Soros? Show Hide Born in Budapest in 1930, the Hungarian-American is one of the world’s most successful investors. He emigrated to the UK as a refugee in 1947, later settling in the US. He made his fortune on Wall Street. He is best known in the UK as "the man who broke the Bank of England" after making a reported $1bn (£720m) profit betting against sterling on Black Wednesday, 16 September 1992, when John Major’s Conservative government was forced to withdraw sterling from the European Exchange Rate Mechanism. His human rights foundation, Open Society Foundations, is the third largest charitable foundation in the world, behind the Bill and Melinda Gates Foundation and the Wellcome Trust. The foundation has funded NGOs advancing human rights, the rule of law, education, public health, LGBT and Roma rights, a free press, and public transport networks across central and eastern Europe and in more than 120 countries. He is the 29th richest man in the world. Last year he transferred about $18bn to the foundation, bringing his lifetime giving to $32bn. Soros has campaigned for years for democracy, human rights and open borders in the former eastern bloc. Increasingly, however, he has become a global hate figure for nationalists and populists. In the US, Soros’s support for LGBT rights groups and campaigning to reduce police violence have made him a target for rightwing attacks, further fuelled by donations to Hillary Clinton’s presidential campaign and a $10m donation to combating hate crime after the election of Donald Trump. Photograph: Sean Gallup/Getty Images Europe

“This process will change Britain and Europe from friends into foes, at least during the transitional period,” he said. “Before the referendum Britain was doing better economically than the rest of Europe. But this has now been reversed, with continental economies powering ahead while Britain lags behind.”

Soros said he believed it was crucial to attempt to change people’s minds about leaving the EU. Referendum votes often saw one side “egged on by unscrupulous agitators” he said, adding that “people use them to express their dissatisfaction with the current state of affairs rather than contemplating the consequences”.

The 87-year-old said he was also concerned about the divisions between rich and poor over Brexit. “Old voters have overruled young voters who will have to live with the consequences of Brexit for decades ahead. This is aggravating the disillusionment with democracy among young people,” he said.

“But a mere reversal of the 52:48 majority for Brexit is not enough. The majority for staying would have to be significantly larger to convince Europe that Britain’s attitude towards Europe has fundamentally changed and its decision deserves to be taken seriously.”

Soros said he believed public opinion was slowly shifting in Britain, but that time was running out and a tipping point needed to be reached in the next six to nine months.

“Best for Britain seeks to break the logjam by bringing together all the various forces that are united by their aspiration for Britain to remain part of Europe. It has my wholehearted support,” he said.

Best for Britain, which advocates remaining in the EU rather than fighting for a soft Brexit, received the six-figure sum from OSF since the June 2017 election. The campaign is chaired by Mark Malloch-Brown, a former UK government minister and deputy UN secretary general.

It was co-founded by Gina Miller, who took the UK government to court over the triggering of the article 50 process to leave the EU. Miller has since said she is no longer part of the organisation, which she has accused of being undemocratic.

Lord Malloch-Brown said the campaign group had followed all rules and regulations governing financial contribution. “We, like millions of people, believe that Britain should lead, not leave, Europe,” he said.

“We work with campaigners, businesses, unions, politicians and community groups to make sure everyone has a strong campaigning voice,” he said.