Nigel Farage is channelling Donald Trump's brand of angry populism to help turn British politics on its head.

"You are in denial, the BBC is in denial, the Tory and Labour parties are in denial," the nationalist poster boy of the 2016 campaign to get Britain out of the European Union told the broadcaster in a feisty interview.

"I think you are all in for a bigger surprise than you can even imagine," he said of the May 23 elections.

The rise and rise of the 55-year-old former commodities trader is one of the most immediate and striking consequences of May's failure to lead Britain out of the European Union on time.

Britain was meant to have split away after 46 years on March 29.

May's inability to force her EU divorce deal through parliament has pushed that back until October 31.

Some think the date may have to be delayed further still -- giving EU supporters time to reverse Brexit.