Britain should go for a no-deal Brexit with the EU and refuse to pay the agreed £39 billion (45 billion euros, $50 billion) divorce bill, U.S. President Donald Trump told The Sunday Times newspaper on the eve of a visit to London.

 

The comments by America's outspoken leader came after he told The Sun newspaper he thought former foreign secretary Boris Johnson would make an "excellent" prime minister to take over from Theresa May, the current leader who is to resign June 7 after failing to get her EU divorce text through parliament.

 

Trump is to embark on a three-day state visit to Britain from Monday, during which he will meet Queen Elizabeth II and have talks with May.

 

In his interview with The Sunday Times, he urged Britain's government to follow his rule book in negotiating deals when it came to Brexit.

 

"If they don't get what they want, I would walk away... If you don't get the deal you want, if you don't get a fair deal, then you walk away," he said.

 

On the divorce bill -- Britain's liabilities as it leaves an economic and political bloc it has been part of since 1973 -- Trump told the newspaper: "If I were them I wouldn't pay $50 billion. That is me. I would not pay, that is a tremendous number."

 

The U.S. president, who is proud of his disruptive influence on politics in America and abroad, also said Britain's anti-EU and populist politician Nigel Farage, head of the Brexit Party, should be involved in negotiating his country's exit from the European Union.

 

"He is a very smart person" with a "lot to offer", said Trump, although he acknowledged that British authorities "won't bring him in."

 

- Conservatives riven -

 

A majority of British voters decided in a 2016 referendum to leave the European Union. The exit was meant to have happened in March this year but as been pushed back twice as Britain has been locked in an impasse on how to achieve it.

 

The ruling Conservative party under May and the parliament are riven by what sort of Brexit they want: either a total break from the EU, or a closer relationship that implies accepting EU rules on trade and immigration.

 

After failing repeatedly to get her vision of Brexit passed, May has been forced to announce she will step down on Friday. More than a dozen Conservative MPs have thrown their hat in the ring to take over as party leader and prime minister, with Johnson seen as an early favorite.

 

Britain is hoping Trump's visit will bolster its ambitions to work out a free trade deal with the United States if Brexit means a go-it-alone trade policy. 

 

Some Conservatives and the opposition Labour party, however, fear Britain would be steamrolled by the far bigger U.S. into accepting an unbalanced accord, especially given Trump's "America First" stance in shaking up trade ties with Mexico, Canada, Japan and China.

 

Large protests are planned during Trump's visit to London.

 

The mayor of the capital, Sadiq Khan, said Sunday in a piece in The Observer newspaper that the U.S. president was "one of the most egregious examples" of a growing global threat from the far-right.

 

Khan said Trump's "divisive behavior flies in the face of the ideals America was founded upon -- equality, liberty and religious freedom."

 

He added that populist politicians such as Farage and Hungary's Prime Minister Viktor Orban "are using the same divisive tropes of the fascists of the 20th century to garner support, but are using new sinister methods to deliver their message."