Return of extremism will complicate Brexit in 2018, says Blackstone’s Studzinski

• Populism could derail Brexit deal says Blackstone's John Studzinski
• He says the shape of Brexit looks set to change dramatically
• Lord Malloch Brown says "soft Brexit" could bring a change of U.K. government

A heavy defeat for the right-wing politician Marine Le Pen in May's French presidential election was touted as evidence that populism in Europe was on the wane.

But the vice-chairman of Blackstone believes that moment was just a lull and voices from the fringe will again be heard loud and clear next year.

"In 2018, I do believe the drivers of populist movements, given that 2017 was a fairly placid year on populism, are going to be far rifer to both the far-right and far-left," said John Studzinski.

"That will make the whole Brexit and European Union debate much more complicated."

Studzinksi said Britain's exit from Europe was still at a very early stage and he expected to see a redefinition of what Brexit means as negotiations evolve.

"There is no question that Europe sees its own future and stability and a sort of troika relationship among Germany, France and the U.K.," he said. "People like Merkel and Macron would love to keep May and the U.K. in the EU."

But the former United Nations Deputy Secretary-General Lord Malloch Brown said division within the U.K. means Europe's power brokers won't rush to bring the country back into its fold.

"It (U.K.) can't get Brexit through because it has a weak government and a conflicted parliament. Is that the terms in which you want to reimport Britain's civil war into the debate about Europe?"

Malloch Brown said he agreed with Studzinksi's view that a "hard Brexit" looks much less likely for Britain. He added that the result could be disastrous for both those who believe in Brexit and May's ruling Conservative party.

"I can now see a likely parliamentary vote against Mrs May's Brexit and that could lead to both a new general election and shift to a Corbyn government, or another referendum," he said.

For the full interview watch CNBC's special "The Davos Guide" program. Episode 1 airing on Tues Dec 26 at 23:00 CET and Weds Dec 27 07:30 CET. Episode 2 airing on Weds Dec 27 23:00 CET and Thurs Dec 28 07:30 CET. Episode 3 airing on Thurs Dec 28 at 23:00 CET and Fri Dec 29 at 07:30 CET.