If Leave loses, will they take the Conservative Party down with them?

Few but the most passionate Leave campaigners now believe there is any serious prospect of the UK voting to leave the European Union on June 23rd.

The Remain campaign's relentless fear-mongering has crowded out any attempt to set out a positive case for EU membership, but it seems their cynicism was well-placed.

Barring a pitifully low turnout, it seems Britain will vote to stay in an institution it still feels very luke-warm about. Leave campaigners already mutter darkly that anything short of a landslide result will leave the door open to a second referendum.

Meanwhile, we will remain a semi-detached member, retaining our suspicions about other countries' true motives, and exasperating them with our half-hearted membership.

What, then, was the point of the referendum campaign? If it was meant to draw the poison from the Conservative Party, it may be seen as David Cameron's biggest failure.

So many leaflets and banners, so many angry tweets, so many broken political friendships, and for what?

Calling this referendum was no act of strength by Mr Cameron, but instead came from a position of weakness. He offered it to head off pre-election defections to UKIP, from within his party or its supporters. And he offered it, half expecting the promise would be sacrificed in negotiations for another coalition agreement.

Instead, he found himself nursing a tiny majority, one that’s far outnumbered by the Conservative MPs desperate to take Britain out of the EU.

The party's inexplicable obsession with Brussels, and questions of sovereignty, again threatens to undermine a Tory leader, and overshadow a leadership race.

Mr Cameron had to allow his ministers to campaign on either side of the debate. But the ferocity of the attacks Conservatives have been willing to launch on each other will sour relations for years, a lesson the Tories never quite seem to learn.

Iain Duncan-Smith resigned, to lob grenades at Downing Street that go beyond his Euro-scepticism, while Boris Johnson and Michael Gove openly ridicule the Prime Minister’s promise to cut migration to the "tens of thousands".

For every terrifying warning of economic collapse or war, the Leave camp have responded with a campaign increasingly semi-detached from the real world. Few people now believe their figures, and complaints about migration sometimes veer uncomfortably close to outright racism.

Yet for some on the Brexit side, too much has been said for them to march hand-in-hand into the future on June 24th -- they may lose the referendum, but win a final victory in a purge of Remainers, starting at the very top.

It would take fifty Conservative MPs to trigger a challenge to David Cameron’s leadership, which seems unlikely. Far more likely that around half that number will coalesce into a permanent awkward squad. Bigger than the Tories' majority, they'll make life as difficult as possible for the Prime Minister, undermining his leadership in the hope of triggering Mr Cameron's early departure, and replacement with a confirmed Brexiteer.

Some even want an early election, maybe even this Autumn. Fixed term parliaments make that hard to achieve, but not impossible.

This band of furious Tories think Labour’s disarray make their disunity affordable. Voters don’t like divided parties, but they’re unlikely to risk Jeremy Corbyn instead.

Labour’s near-total absence from the referendum campaign has allowed the Tories’ internal battles to dominate. Maybe there was a vague strategy behind that, from people who remember how Europe destroyed John Major’s government in the 1990s.

But Mr Major faced a rigidly disciplined Labour party, focused solely on winning the next election. The situation is rather different this time.

Still, some Labour MPs might welcome an early election. Defeat would presumably end the Corbyn leadership, giving them a chance to rebuild, earlier than they might have expected.

Our relationship with the rest of Europe has always had unintended consequences. More are likely to tumble from the result of this referendum…