Nigel Farage urged Republicans to donate to Bernie Sanders' campaign to boost Donald Trump's re-election chance as he addressed America's largest gathering of grassroots conservatives on Friday.

"You should be backing Bernie Sanders, you should be campaigning for Bernie Sanders, you should be donating money to Bernie Sanders," he told the audience at the Conservative Political Action Conference (CPAC).

Mr Farage said that Mr Sanders, a self-declared democratic socialist and the current front runner in the Democratic nomination race, offered the best hope of Mr Trump winning a second term in office in November's presidential election.

"You need a Democrat Party that's as far left-wing and as anti-American as they possibly can be," he said, adding that Mr Sanders' name on the ballot could also allow Republicans to regain a majority in the US House of Representatives.

Mr Farage drew a comparison with the UK, telling the audience that there was a "lesson" to be learned from Jeremy Corbyn's leadership of the Labour Party, calling it a "huge contributory factor to Brexit getting done" and to Boris Johnson winning a majority.