It is quite normal in British politics for a political party to turn on itself after an election defeat — but the Tories now seem to be preparing themselves for civil war in the unlikely event of victory. Already, the tribes are forming and snarling at each other. As ever, Europe is the casus belli. Ahead of the 2017 in/out EU referendum, the Tories will probably split into not two but three groups: the in crowd, the out crowd and the reform crowd.

The fighting has already started. Take the struggle to lead the ‘out’ faction. It is at present being won by Owen Paterson, who in the last three days has been prowling television studios like a general who has just staged a successful military coup. The other contenders include the two men who opposed David Cameron for the party’s leadership — Liam Fox and David Davis — as well as ministers such as Chris Grayling, who must stay silent while in office. They can expect to be backed by about three or four dozen MPs who already want to leave the EU — regardless of what spoils the Prime Minister brings back from Brussels.

The outers know that if David Cameron is Prime Minister after the 2015 election, the party will be awash with malcontents — many of them people (disproportionally male) who have been sacked to make way for fresh faces (dis-proportionally female) in a new government. They will be looking forward to Cameron losing a 2017 referendum and being forced to stand down. If Cameron campaigns to stay in the EU but the country votes to leave, then whoever led the ‘out’ campaign would have a strong claim to take over as Tory leader. No wonder senior MPs like Paterson are getting their job applications in early. Davis has also talked to colleagues about how he could reunite the party after the referendum.

The ‘in’ crowd imagine a 2017 victory, and the latest polls suggest they might not be deluded. Some of their senior representatives believe that an in vote would allow Cameron to tell his critics where to stick it. They clearly haven’t noticed what has happened in Scotland since the referendum there. Alex Salmond has demonstrated that a referendum settles nothing.

The ‘in’ and ‘out’ sides expect to face each other, and are formulating their strategies accordingly. But the reformers in the middle — those who would vote to stay in Europe but are optimistic about changing Britain’s relationship with the EU — are the biggest and most powerful group. These moderates are growing tired of having to march through the voting lobbies with headbanging rebels every time another revolt is staged in the Commons. The Peter Bones of the Conservative party are vastly outnumbered by the moderate Eurosceptics — but most MPs feel they have to rebel in order to avoid being labelled Europhile.

These moderate Eurosceptics may start suggesting that their hardcore colleagues follow Douglas Carswell and join Ukip. The hardcore might even agree. Tory members of various groups such as No Turning Back, Cornerstone and Free Enterprise say they have already ‘war-gamed’ the possibility of a good number of their members defecting to Ukip after the general election. They calculate that Nigel Farage will secure about a dozen MPs. They also suspect that some of the left-leaning Tory Europhiles may wish to strike out on their own. There is talk of the Tory left hiving off to become a National Liberal party — a proper home for members of the much-derided liberal metropolitan elite.

We may not have to wait until 2017 to see this crack-up. One robustly Eurosceptic Tory minister tells me that it could happen next year if the election delivers an inconclusive result. ‘I can just see that Cameron returns to us without a majority, at which point the eyes will roll back in the heads of my headbanging colleagues and they will make all sorts of demands on him. And the rest of us will tell them to get stuffed,’ he says. Another senior Tory says that ‘Yes, we are sick and bloody tired of having 30 or 40 Peter Bones putting a gun to the Prime Minister’s head and jerking him around. There is a nutter Eurosceptic tail wagging the rest of the dog.’

The Tory party breaking up into three parts might be an attractive proposition for members of all three factions. But it would be electoral suicide. So many left-wing Tory MPs will be leaving parliament in 2015: the Liberal Metropolitan Conservatives will not be able to fill one bench in the Commons, let alone become a political force. How-ever frustrated moderate Eurosceptics are at being wagged about by their ‘nutter Eurosceptic tail’, they will probably need those colleagues even more after the general -election.

We can at the very least expect Tory wars to continue for the next few years. They have so far been behaving themselves reasonably well because they don’t want the humiliation of being beaten by the unimpressive Ed Miliband. They joke quite openly that their loyalty to the Prime Minister only extends to election day. Their loyalty to one another is even more tenuous.