In 1945, after Winston Churchill proposed holding a referendum 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. Thirty years passed before a prime minister disregarded this convention, with Harold Wilson calling a vote on the continued membership of the European Economic Community.

The EU vote on 23 June was Britain’s third national referendum, yet it was the first that did not confirm the status quo. Leavers such as Boris Johnson and Nigel Farage spoke with revolutionary ardour of “independence day”. A new state had been declared: Brexitannia. However, the institutions of the old country endured: parliament, the Bank of England, the Treasury and the high court. Coexistence is proving troublesome.

Had David Cameron not resigned, he would probably have become the revolution’s first victim. The Bank of England governor, Mark Carney, who antagonised Brexiteers with his economic warnings, swiftly became an alternative target. Theresa May’s declaration that “a change has got to come” in a passage on the Bank’s monetary policies in her first speech as Prime Minister was regarded as licence to challenge Carney. He eventually resolved to depart in June 2019.

Three days after Carney’s announcement, the high court ruled that a parliamentary vote was required to trigger Article 50, the official process for leaving the EU. The decision was consistent with the British constitution but, in the post-referendum world, the judges were cast as counter-revolutionaries. The Communities Secretary, Sajid Javid, warned of “an attempt to frustrate the will of the British people”. The Ukip leadership candidate Suzanne Evans suggested that the judges should be “subject to some kind of democratic control”. Past revolutionaries established “people’s courts” for this purpose.

In their disregard for convention, the Brexiteers owe more to Jacobins than conservatives. Patient constitutionalists such as the former attorney general Dominic Grieve, horrified by the Leavers’ anti-traditionalism, resemble Edmund Burke at the time of the French Revolution.

If, as the government anticipates, its Article 50 appeal is defeated in the Supreme Court, the Brexiteers will face a new foe: parliament. Although MPs have no intention of blocking EU withdrawal (save Ken Clarke), they will try to influence its shape. The government’s working majority of 14 seats gives them ample opportunity to do so.

The Liberal Democrats, and likely Labour, will amend any legislation to support the aim of full access to the single market. Tory Remainers, such as Nicky Morgan and Anna Soubry, intend to join the rebellion when the “Great Repeal Bill” is published next spring. Cross-party alliances forged during the referendum have been sustained by Open Britain, the successor group to the Remain campaign.

MPs have a duty to act as representatives, not delegates, and they have their own democratic mandate. Their House of Lords counterparts do not. Mindful of this, peers dismiss the possibility of thwarting Brexit. “We’re not blocking it. We’re not playing games,” the Labour Lords leader, Angela Smith, said. But she added: “The Lords will come into its own on the detail of negotiations . . . It’s about the lack of confidence that the government knows what it’s doing.” Brexiteers who blocked Lords reform in 2012 are already becoming converts to change.

Senior Leavers, such as Iain Duncan Smith and Dominic Raab, have warned May to prepare for an early general election if parliament obstructs her will. Tory MPs note a subtle shift in her language. Rather than stating that the next election “will be” in 2020, May remarked during her India trip that it “should be”. The Prime Minister does not desire an early election but she recognises that conditions may necessitate one.

As a “reluctant Remainer”, May is liable to be accused of betrayal by both sides. Her priority has been to earn credibility among Leavers. Had she refused to endorse “hard Brexit”, she would have positioned herself against the majority of Conservative MPs and activists. Yet she could struggle to hold the centre in her cabinet. Philip Hammond quickly became the subject of hostile briefing. The Chancellor’s aim of preserving the UK’s membership of the customs union has put him unavoidably at odds with the International Trade Secretary, Liam Fox. Remainers contend that Hammond, like the judges, is merely doing his job. But in the post-referendum era, loyalty to the revolution trumps all. Although relations between Hammond and the Brexit Secretary, David Davis, have thawed, those with Fox remain fraught.

Unlike her Chancellor, May has emphasised the need to control immigration. Yet she, too, has served notice of compromises to come. “It will require some give and take,” she warned of the negotiation in her Conservative conference speech. May has said much about the “take” and little about the “give”. The latter is likely to include substantial EU budget contributions. Civil servants recently opened a sweepstake on which of the “Three Brexiteers” – Davis, Fox and Johnson – would be the first to resign. Fox is the favourite.

In political life, “unelected” has become the new pejorative of choice. Institutions purposefully placed at one remove from the people are dismissed as illegitimate. As long as May abides by their wishes, the Leavers will not deploy this charge against her. Yet some are already poised to cry “betrayal” at the first hint of compromise. The Brexit revolutionaries are confronting anyone and anything that constrains them. May should not assume that she will be spared.