Could it happen here? In Britain, liberals watch horrified as Donald Trump tramples on the norms of US democracy. The compliance of the Republican Party and Trump’s shamelessness mean that America’s cherished “checks and balances” have offered little defence.

Yet the disturbing truth is that the UK is still more vulnerable to authoritarianism. Britain’s centralised political model, its unwritten constitution and its arcane electoral system are all gifts to aspirant tyrants. As Steve Bannon’s far-right movement prepares to target the UK (he has met Boris Johnson, Michael Gove and Jacob Rees-Mogg), these defects bear repeating.

Matters have at least improved since Lord Hailsham warned in 1976 of the danger of an “elective dictatorship”. Under the last Labour government, the Human Rights Act was passed, London, Scotland and Wales were granted devolution, most hereditary peers were removed from the House of Lords and a freedom of information law was introduced (much to Tony Blair’s later regret: "You idiot. You naive, foolish, irresponsible nincompoop,” he self-reproachingly wrote in his memoirs).

But the British political system is still easily manipulable. A UK prime minister – provided they have a majority in the House of Commons – is almost unrivalled in their power in Europe. They rule one of the most centralised states in the developed world (with local government enfeebled by austerity), are able to declare war without parliamentary approval – as Theresa May did over Syria – to appoint cabinet ministers and peers (without any confirmation hearings) and to override the House of Lords through the Parliament Act.

The electorate’s recent habit of returning governments with only small majorities – or no majority at all – has acted as a de facto check and balance (no party has won a comfortable majority since 2005 and the Tories haven’t since 1987). But the threat of an elective dictatorship endures.

The Brexit vote has merely heightened the risk. In 1945, after Winston Churchill proposed holding a plebiscite on the extension of the wartime coalition, his then deputy, Clement Attlee, replied: “I could not consent to the introduction into our national life of a device so alien to all our traditions.” The Labour leader feared that such an act would subvert the UK’s delicate, unwritten constitution.

Two referendums – one on the European Economic Community in 1975 and one on replacing the first past the post system with the Alternative Vote in 2011 – would eventually follow. But the EU vote on 23 June 2016 was the first that did not affirm the status quo. As Attlee warned, this act of direct democracy is upending once cherished traditions.

For decades, Eurosceptics revered the UK's unwritten constitution: its sovereign parliament, its independent judiciary, its neutral civil service. But an alternative centre of power – the people – has now been established. Rather than their loyalty to the constitution, institutions are now judged according to their loyalty to the demos (nearly half of whom voted to Remain).

The elected Commons is no more respected. Britain’s supposedly sovereign parliament was initially denied a vote on triggering Article 50 (before the judiciary, or “enemies of the people”, intervened). MPs have had to struggle to secure anything close to a “meaningful vote” on the Brexit deal – and could yet fail to prevent the UK leaving with no deal at all.

Post-Brexit Britain – a land of broken promises and disappointed expectations – will be fertile territory for the far right. A demagogic Prime Minister, with a large Commons majority, would be a terrifying force.

Britain’s institutions and political culture may yet prove robust enough to withstand this threat. But wise democracies prepare for the worst. The UK is unprepared.