Former UK prime minister Boris Johnson has argued that Donald Trump brought “peace and relative stability” during his tenure as US president, while Succession’s Brian Cox described him as a “monster”.

The pair appeared as guests on Channel 4’s live coverage of the US election in the Washington DC studio as the US public decides whether Democratic nominee Kamala Harris or Republican Mr Trump becomes elected.

“We have to make sure that he doesn’t get in because he is a monster, he really is,” Scottish actor Cox said of Mr Trump, as he appeared virtually from London.

“He’s crazy, he’s insane, he wants to be a dictator.

“…I think he’s lost it, quite frankly, I think he’s deeply mentally unstable and I think he has been for some time. This is not a man who should be the president of the United States, absolutely not.

“He’s unreliable, he’s a convicted felon, I’m horrified.”

It came after Mr Johnson explained that he did not think fears about Mr Trump becoming president were accurate, including that he would “give away” Ukraine to Russia.

In response, Cox said: “It’s ridiculous, of course he will. He’ll do what suits him. He’ll do what suits Donald Trump.

“…The man is completely self-serving, he is totally self-serving, he is only interested in one thing, and that’s Donald Trump.

“He doesn’t give a damn about America, he really doesn’t.”

Mr Johnson said he disagreed with Cox regarding Mr Trump’s response to the Ukraine-Russia war if he was elected president.

“I think he will come to it and he will see that if he surrenders, if he allows (Vladimir) Putin to win – for his pride, for his ego, it’s a disaster – it’s a disaster for America, it’s a disaster for the world,” Mr Johnson said.

“You can say that I’m wrong and I’m starry-eyed, and it’s not going to work out like that, and he’ll find a way of surrendering to Putin that somehow protects his reputation, his legacy.

“I don’t see how you do that – it’s a pretty unpolishable turd to be frank.”

Cox retorted: “I don’t buy it, I don’t buy any of it.”

Mr Johnson later said that as a British Conservative politician he did not agree with Mr Trump’s position on female reproductive health, gun control and tariffs.

“I’m not here to stick up for any particular presidential candidate, the 60-year-old said.

He continued: “I think when you look at what Donald Trump actually did in office on the foreign policy front, which is what obviously I care about primarily as the former UK prime minister – from the Abraham accords to Ukraine to Iran – you can make a very strong case that he brought peace and relative stability and I think that’s a very, very important consideration.”

Cox concluded saying he would never play Mr Trump in a film or TV series because “it’s a terribly bad part, nobody would want to play Donald Trump because it’s such a terrible role… how do you find any redeeming feature in the human being”.

Their comments came after Stormy Daniels, the woman at the centre of Mr Trump’s hush money trial following an affair, asked Mr Johnson: “Would you leave your daughter alone with Donald Trump?” after Mr Johnson described their friendship.

“I don’t see why not…yes,” Mr Johnson said, before describing his experience of Mr Trump as “courteous” and “polite”.

When asked if while working with Mr Trump he had feared for the women in his life, Mr Johnson added: “Nothing like that came up, of course not, because when you’re talking to the US president, the relationship you have as UK prime minister is one of great formality and importance.

“And yes of course you develop a friendship, but actually, and I can say this in all sincerity, I never in my time with him was treated with anything other than complete courtesy and friendliness.”