“The time for trivial fights is over” was the most striking sentence in Donald Trump’s surprisingly statesmanlike speech to both houses of Congress. His call for Americans to come together was in sharp contrast to his divisive, rabble-rousing inauguration address in January, which was like his greatest hits on the campaign trail.

The world will now watch the President’s Twitter account to see whether he stops picking “trivial fights”. If he really moves to the mainstream and realises that his aggressive, tribal approach is not working, that will be a huge relief. Yet I doubt it will last, or that there will now be an outbreak of mutual affection between Trump and the “liberal media” he accuses of peddling “fake news” when it tells the truth about his administration, or asks highly-relevant questions about its relations with Russia.

Trump’s dilemma – how mainstream should insurgents become? – now confronts Ukip as it wages civil war via Twitter. Nigel Farage told BBC Radio 4 on Wednesday: “There have been some in Ukip who want to turn us into a mainstream political party with very bland messages and I would say Ukip is a radical party or it is nothing.” He wants a Trump-like approach to immigration to be Ukip’s new cause after Brexit, putting him at odds with Douglas Carswell, the party’s only MP.

Donald Trump takes credit for companies' investments that began before he became President

Thankfully Ukip remains a million miles from power; perhaps there is some merit to our outdated first-past-the-post electoral system after all. Yet those politicians who believe a Trump-like figure could “never happen here” cannot be complacent, even after Ukip’s humiliating defeat in Stoke-on-Trent Central. Ukip won the 2014 European Parliament elections, fought under the fairer proportional representation system, and almost 4 million people voted for it at the 2015 general election.

The vote for Brexit showed that anything can happen here as well as across the Atlantic. We would be unwise to assume that it could never happen at a general election just because voters had left off steam in a referendum.

In the short term, it’s unlikely. What Ukip needs more than anything is for Theresa May to fail to deliver Brexit – but it will be disappointed. May knows that if we have not left the EU by a 2020 general election, she might face just the sort of uprising we saw in last year’s referendum. The next best scenario for Ukip would be for May to negotiate a soft Brexit which does little to reduce immigration. Possible, but unlikely; the Prime Minister prioritises immigration over close trading links.

Although the US and UK political systems are different, those who believe Trump couldn’t happen here should remember that we often follow America. Our politics has become more presidential; we now have a huge lobbying industry and a Supreme Court. New Labour copied the campaign and media techniques of Bill Clinton’s New Democrats. The new political class of young advisers, many of them now MPs, worshipped The West Wing. David Cameron followed the New Labour playbook. The result was a long period of government-by-headline which May has now brought to an end.

After the Tories’ sensational victory in Copeland, May has every chance of colonising the centre ground. With Ukip marginalised, the best chance of seeing a Trump-like populist emerge anytime soon in Britain is on the left.

Trump Inauguration protests around the World Show all 14 1 /14 Trump Inauguration protests around the World Trump Inauguration protests around the World Activists from Greenpeace display a message reading "Mr President, walls divide. Build Bridges!" along the Berlin wall in Berlin on January 20, 2017 to coincide with the inauguration of Donald Trump as the 45th president of the United State Getty Trump Inauguration protests around the World An activist holds up a sign at the "We Stand United" rally on the eve of US President-elect Donald Trump's inauguration outside Trump International Hotel and Tower in New York on January 19, 2017 in New York Getty Trump Inauguration protests around the World Protesters burn a U.S. flag and a mock flag with pictures of U.S. President-elect Donald Trump outside the U.S. embassy in metro Manila, Philippines Getty Trump Inauguration protests around the World Filipino protestors hold placcards during a protest rally in front of the US embassy in Manila, Philippines, 20 January 2017. On the eve of President-elect Donald Trump's inaguration as the 45th president of the United States, Filipinos and Fil-Americans held a protest in front of the US embassy in Manila to denounce the incoming US president. Getty Trump Inauguration protests around the World Hong Kong police officers and security guards look on as an anarchist protester belonging to the Disrupt J20 movement sits after using a heavy duty D-lock and motorcycle lock to chain himself to a railing at the entrance gate to the Consulate General of the United States of America in Hong Kong to protest the inauguration of United States President-elect Donald Trump, Hong Kong, China, 20 January 2017. Two activists were arrested and taken away by Hong Kong police during the demonstration. Getty Trump Inauguration protests around the World A banner is unfurled on London's Tower Bridge, organised by Bridges Not Walls - a partnership between grassroots activists and campaigners working on a range of issues, formed in the wake of Donald Trump's election, which aims to build bridges to a world free from hatred and oppression. Getty Trump Inauguration protests around the World Protesters chain themselves to an entry point prior at the inauguration of U.S. President-elect Donald Trump in Washington, DC, U.S. Getty Trump Inauguration protests around the World Bridges Not Walls banner dropped from Molenbeek bridge in Brussels, Belgium, 20 January 2017, in an Greenpeace action part of protests Wolrd protest in solidarity with people in the US, the day Donald Trump sworn in as the 45th President of the United States. Getty Trump Inauguration protests around the World A woman holds an anti-U.S. President-elect Donald Trump placard during a rally in Tokyo, Japan, Getty Trump Inauguration protests around the World A Palestinian protester holds a placard during a demonstration against the construction of Jewish settlements in the occupied West Bank and against US President-elect Donald Trump, on January 20, 2017, near the settlement of Maale Adumim, east of Jerusalem Getty Trump Inauguration protests around the World Banners on North Bridge in Edinburgh as part of the Bridges Not Walls protest against US President Donald Trump on the day of his inauguration Getty Trump Inauguration protests around the World Russian artist Vasily Slonov (L) and his assistant carry a life-sized cutout, which is an artwork created by Slonov and titled "Siberian Inauguration", before its presentation on the occasion of the inauguration of U.S. President-elect Donald Trump, in a street in Krasnoyarsk, Russia Getty Trump Inauguration protests around the World A woman holds a banner during a march to thank outgoing President Barack Obama and reject US President-elect Donald Trump before his inauguration at a park in Tokyo, Japan, 20 January 2017. EPA Trump Inauguration protests around the World Palestinian demonstrators protesting this week against a promise by Donald Trump to re-locate the US embassy to Jerusalem Reuters

Arguably we already have one in Jeremy Corbyn who, like Trump, persuaded a mainstream party to elect him against all the odds and won a personality cult. Corbyn advisers hoped he would become an anti-establishment hero. Their hatred of New Labour made them hostile to communicating through the mainstream media which, ludicrously, they blame for Labour’s dire performance. If we play fantasy politics for a moment and imagine Prime Minister Corbyn, it is easy to see him mirroring Trump and tweeting from Number 10 about “fake news.”

Back in the real world, Labour belatedly promises new policies and a coherent message. It could be Corbyn’s last chance to persuade his party to stick with him until the general election, but might already be too late.

If we are to see a left-wing version of Trump in office in Britain, it won’t be Corbyn. Labour centrists dream that a new hero will sweep to power in the party and country like Emmanuel Macron, who emerged from nowhere to become a serious contender in the French Presidential election. Some do not rule out an SDP-style breakaway after the next election, even though the “Gang of Four” who left Labour in 1981 failed – just – to break the political mould.