Trump backs "fantastic" Boris over "bad" Corbyn ahead of UK polls

US President Donald Trump ruffled a few feathers in the UK with an intervention on the country's upcoming General Election by backing his "friend" UK Prime Minister Boris Johnson and categorising Opposition Labour Party Leader Jeremy Corbyn as "so bad" for Britain.

In an interview with LBC Radio with host and far-right Brexit Party Leader Nigel Farage on the phone overnight on Thursday, Trump pushed for an alliance between the Conservatives and Farage's party as an "unstoppable" force for the December 12 polls.

"I have great relationships with many of the leaders, including Boris who's a fantastic man I think he's the exact right guy for the times," Trump said.

"I know that you and him will end up doing something that could be terrific if you and he get together it's [an] unstoppable force," he said.

In reference to Corbyn, the US President was scathing.

"Corbyn would be so bad for your country, he'd be so bad, he'd take you in such a bad way. He'd take you into such bad places. But your country has tremendous potential, it's a great country," Trump said.

The remarks prompted Corbyn to take to Twitter to accuse the US President of "trying to interfere" in Britain's internal affairs to get "his friend Boris Johnson elected".

However, in his characteristic style, Trump went on to also criticise Johnson for his Brexit deal struck with the European Union (EU), as damaging for US-UK trade relations, forcing Downing Street to dismiss the concerns.

Trump said, "Under certain aspects of the deal you can't do it [sign a trade deal with the US]. You can't do it, you can't trade, we can't make a trade deal with the UK.

"I think we can do many times the numbers that we're doing right now and certainly much bigger numbers than you're doing under the EU. So, I know Boris wants to be very careful of that."