Anand Menon is Professor of European Politics and Foreign Affairs at Kings College London and Director of the UK in a Changing Europe Initiative. Dr Alan Wager is a Researcher at the UK in a Changing Europe Initiative.

The Conservative Party is in turmoil. Just 32 per cent of Conservative MPs who do not currently hold a government job voted for the Government’s Brexit deal. Unless the competing factions of the Party can be reconciled, this risks not merely making the Prime Minister’s life uncomfortable, but also splintering her party.

Yet taking a step back and looking at British politics through the lens of public opinion, it is, on one level, hard to see why Theresa May is in difficulty at all. The Conservative Party, if not in rude health, has certainly seen worse days. Headline voting intention stubbornly puts the Conservative and Labour parties in a near-statistical tie. Public perceptions of May consistently outrank those of Jeremy Corbyn. The Government’s approval rating looks more like a case of mid-term blues than a party on the verge of collapse.

This is because the Conservative Party’s existential crisis is primarily internal. The likelihood of a split is exacerbated not just by the sheer numbers on each side of the Tory Brexit divide, but its nature. On Brexit, the instincts of the Party’s 124,000 members and 330 MPs run counter to those who have, for the last 15 years, run the Conservative Party. The views of members and MPs appear irreconcilable with what will be needed in a deal that could command a majority in Parliament.

Take first the members of the Conservative Party. Seventy-five per cent say Brexit is the key issue facing British politics. As Tim Bale, Monica Poletti and Paul Webb outline in this report, the overwhelming majority of members are intensely relaxed about the prospect of a no deal Brexit. Two-thirds of them do not think the Government’s negotiated deal honours the referendum.

As Figure 1 illustrates, more Conservative voters (67 per cent) than Conservative members (51 per cent) think Theresa May is doing a good job as Prime Minister. More Conservative voters (46 per cent) than Conservative members (38 per cent) support Theresa May’s draft Brexit deal. And, according to YouGov and the ESRC’s Party Members Project, 54 per cent of party members who voted Leave thought that, following the defeat of the Government’s deal, Theresa May should have resigned. Ipsos Mori found, somewhat remarkably, that 40 per cent of all voters thought the same, and 53 per cent thought the opposite. So, a lower share of the wider public felt the Prime Minister should have immediately resigned after losing the meaningful vote than of members of her party who voted Leave.

There is a widespread assumption that Conservative MPs, with one eye on the wider electorate, might act as a restraining force on these members. Certainly, the Conservative Party’s leadership rules give them the opportunity to do so.

However, over half of its parliamentarians either do not believe – or have yet to compute – the economic trade-offs that Brexit is likely to involve. It is remarkable that 85 per cent of Conservative MPs – despite the evidence to the contrary – expect any lost trade with the EU following Brexit to be offset by trade with the rest of the world. Only 35 per cent of Conservative MPs accept that there are genuine difficulties to finding a solution to the issue of the Irish border. A denial of the hard choices created by Brexit might well be good internal party politics for prospective leadership candidates. It is not good politics if trying to plot a governing route through Brexit.

If the Conservative Party were universally united behind a hard Brexit, a No Deal and a change of leadership, then the Party would naturally evolve rather than split. Yet it is worth noting a slim majority of members (51 to 48 per cent) continue to think May is doing a good job as leader. This is because the Prime Minister has overwhelming support – by a margin of three-to-one – among the roughly 20 per cent of Tory members who voted Remain and are still party members.

For most of their 200-year history, the Tories have been two parties – one whose instincts are broadly protectionist and nationalist, the other free market and liberal – united, above all, by a singular desire for office. If a terminal split is possible, Brexit will have been a political event that emanated from the Conservative Party, but tore it apart.