Brexit 'a mistake, not a disaster': ex-PM David Cameron

Britain's planned departure from the European Union is "a mistake, not a disaster", former premier David Cameron said during a conversation caught on camera in Davos today.

Cameron stepped back from frontline British politics in the wake of the historic 2016 referendum, but was caught airing his views on Brexit at Switzerland's gathering of the world's business elite.

"It's frustrating. As I keep saying, it's a mistake, not a disaster," he told Indian billionaire businessman Lakshmi Mittal on the sidelines of the economic summit.

"It's turned out less badly than we first thought. But it's still going to be difficult," he added, in a conversation filmed by Britain's Channel 5 News.

Cameron orchestrated the vote on June 23, 2016, in which the country chose to leave the EU, despite himself backing the campaign to remain in the bloc.

He stepped down as prime minister the morning after the referendum, leaving his successor Theresa May to enter fraught EU negotiations with a cabinet divided on Brexit lines.

Britain has said it will leave the union on March 29, 2019, and after reaching an initial agreement on exit terms is due to enter further talks on its future relationship with Brussels later this year.