George Soros says Brexit is a 'tragic mistake.' Credit: Olivier Hoslet/EPA George Soros: I won’t ‘butt out’ of Brexit politics The financier said Brexit was a ‘tragic mistake’ brought about by ‘unscrupulous agitators’ in the referendum.

Financier George Soros has vowed not to "butt out" of supporting a campaign to keep the U.K. in the European Union because Brexit is a "tragic mistake."

The Best for Britain campaign came under fire last week from newspaper articles in the Telegraph and Daily Mail for accepting £400,000 in funding from Soros's Open Society Foundation. But Soros has hit back in a comment piece for the Mail on Sunday, citing his past as a refugee and his foundation's work promoting democracy.

"I am a proud supporter of Best For Britain, a group that wants Britain to remain a member of the European Union. I consider Brexit a tragic mistake," he wrote.

"Prior to Brexit, Britain enjoyed the best of all possible worlds: it was a member of the European Union without adopting the euro."

He said he viewed the decision to hold a referendum on EU membership as a mistake. "Egged on by unscrupulous agitators, people use [referenda] to express their dissatisfaction with the current state of affairs rather than contemplating the consequences. The fact that conditions are unsatisfactory does not mean they can’t get worse. That is what has happened in Britain," he wrote.

He said Brexit would divert the U.K.'s political attention for years and diminish its global influence. But he expressed hope that it can be reversed. "The trend is moving in the right direction. The question is how its momentum can be accelerated so that it reaches a tipping point in the next six to nine months."