The U.K.'s decision to leave the EU is the second most "stupidest" decision ever made by a country, only beaten by the U.S. voting for President Donald Trump, according to Michael Bloomberg.

"I did say that I thought it (Brexit) was the stupidest thing that a country has ever done — but then we trumped it," the media mogul said at a panel event in Boston two weeks ago, unearthed by the Guardian newspaper on Tuesday.

"It is really hard to understand why a country that was doing so well wanted to ruin it," he added. "My former wife was a Brit, my daughters have British passports, so we love England – it's the father of our country, I suppose. But what they are doing is not good and there is no easy ways to get out of it because if they don't pay a penalty, everyone else would drop out. So they can't get as good of a deal as they had before," he said.