LONDON (Reuters) - The leader who triggered the vote that began Britain’s chaotic divorce from the European Union said he never expected the referendum to go ahead as he did not foresee winning the 2015 election outright, European Council President Donald Tusk has said.

FILE PHOTO: Britain's Prime Minister David Cameron walks out of 10 Downing Street to make a statement, in Westminster, London, July 11, 2016. REUTERS/Peter Nicholls/File Photo

Former prime minister David Cameron first pledged a referendum in 2013 while governing in coalition with the pro-EU Liberal Democrats in a bid to placate his party’s eurosceptic wing and fend off support for the anti-EU UK Independence Party.

Cameron’s Conservatives unexpectedly won a majority in the 2015 national election, Britain voted by 52 to 48 percent to leave in the 2016 referendum, and he went on to quit after leading the unsuccessful campaign to remain in the bloc.

“I asked David Cameron, ‘Why did you decide on this referendum, this – it’s so dangerous, so even stupid, you know,’ and, he told me ... that the only reason was his own party,” Tusk told the BBC’s “Inside Europe: Ten Years of Turmoil” program, due to be aired later this month.

“(He told me) he felt really safe, because he thought at the same time that there’s no risk of a referendum because his coalition partner the Liberals would block this idea of a referendum.

“But then, surprisingly, he won and there was no coalition partner. So paradoxically David Cameron became the real victim of his own victory,” Tusk added, describing the referendum as “the biggest mistake” of Cameron’s life.

However, Cameron’s former spokesman Craig Oliver said Tusk’s comments were “completely wrong”.

“David Cameron spent the whole of the 2015 election campaign making clear he would not lead any form of government that didn’t have a referendum,” Oliver wrote on Twitter.

“The coalition as ‘excuse to bail’ is a myth.”

Last week, Cameron told the Daily Mirror newspaper he did not regret calling the referendum after current Prime Minister Theresa May’s Brexit deal was overwhelmingly rejected by lawmakers, including 118 Conservatives.

“It was a promise I made two years before the 2015 general election, it was included in a manifesto, it was legislated for in parliament,” he said. “Obviously I regret that we lost that referendum. I deeply regret that.

“Obviously I regret the difficulties and problems we have been having in trying to implement the result of that referendum.”