The Jewish billionaire whose bet against the pound caused the UK to crash out of the European Exchange Rate Mechanism in 1992 is stumping up £400,000 to keep Britain in the European Union.

George Soros, 87, a Hungarian-American investor who has already donated $18 billion to democracy projects around the world, waded into the Brexit debate on Thursday by saying he would help pay for a campaign to reverse the vote.

Soros was born in 1930, survived Nazi-occupied Hungary and emigrated to Britain in 1947 to begin life as a banker. He later became known as ‘the man who broke the Bank of England’ after betting against the pound, making him $1 billion profit.

His money is being donated to the Best for Britain campaign, which advocates staying in the European Union. It was co-founded Gina Miller, who successfully sued the government over its decision to invoke the Article 50 treaty terms to formally begin the process of leaving the EU, re-establishing the sovereignty of Parliament.

The organisation is chaired by the highly influential former UK government minister and deputy UN secretary-general Lord Malloch-Brown, who took up leadership positions at some of Soros’s funds and institutes in 2007.

In 2013 Malloch-Brown was sued by controversial Israeli billionaire Beny Steinmetz, who claimed the British diplomat had given Soros confidential information which led to a smear campaign against him and his mining company.

The case settled out of court, but last year the allegations led to Steinmetz’s arrest by a joint Israeli-Swiss team on “allegations of large-scale fraud, breach of trust, bribery, obstruction of justice and false registration of corporate documents” with the apparent purpose of money laundering.

Soros is not well-liked in Israel, because his Open Society Foundation has vowed to “challenge Israel’s racist and anti-democratic policies,” a reference to the policies of successive Benjamin Netanyahu governments.

In Hungary, Soros’s progressive and liberal focus has also upset the right-wing authoritarian government, and he was recently the subject of a government-supported anti-Semitic smear campaign.

The philanthropist has spent millions of dollars supporting the left-leaning Central European University in Budapest, which is seen as the intellectual home of the Hungarian government’s critics.