Meet the “Runnymede Tories”. The most prominent of their number, David Davis, likes the label, so it might just stick: shorthand for those Conservatives compelled by a strong belief in civil liberties and the tradition of ancestral freedoms, enshrined in Magna Carta on the meadowed banks of the Thames eight centuries ago.

As an animating force, this conviction is more than the heritage-loving sentimentalism to which some Tories are indeed prone. In fact, it may be responsible for some of the new government’s most perilous moments in parliament. For a party that needed the Liberal Democrats to govern in its first term, to win a 12-seat majority was a historic achievement. But the scale of that achievement does not alter the brute fact: 12 is only 12.

I have long urged the Cameron camp to make its peace with Davis, who was raised by a single mother on a council estate, is an experienced businessman and personifies the “blue-collar conservatism” that the prime minister now endorses. But Davis has not been forgiven by the Tory leadership for resigning his seat in June 2008, over Labour’s plan to extend the maximum period of detention of terror suspects without charge from 28 to 42 days. Seven years on, he fully expects to be at the heart of one of this government’s first significant defeats.

To set the scene: Michael Gove, the new justice secretary, has been tasked with fulfilling the Tory manifesto’s pledge to “scrap the Human Rights Act, and introduce a British bill of rights”. Once enacted, the bill “will break the formal link between British courts and the European court of human rights, and make our own supreme court the ultimate arbiter of human rights matters in the UK”.

Runnymede Tories believe that Blair and his successors have exploited the fear generated by terrorism to curtail rights

Runnymede Tories such as Dominic Grieve and Ken Clarke (both QCs) are not like the Eurosceptic “bastards” who made John Major’s life a living hell. They do not operate as a cohesive gang or a whipped party-within-a-party – not yet, anyway. Some, such as Jesse Norman, the Tory MP for Hereford and South Herefordshire, want to keep the Human Rights Act. Others are content for it to be replaced by a British bill of rights – provided the bill is sufficiently robust as a bulwark against the over-mighty state. Meanwhile, Dominic Raab, MP for Esher and Walton, Davis’s former chief of staff and author of the Runnymede Tories’ founding tract, The Assault on Liberty (2009), has been made a justice minister. Has he been bought off by Big Brother, or do the Tory civil libertarians now have a man on the inside?

All parties are always, to a greater or lesser degree, split, often around many axes. For decades, the Conservatives were divided into “wets” and “dries”, then “Eurosceptics” and “Europhiles”, then socially liberal “mods” and morally upright “rockers”. These bifurcations persist. But the argument that is most intriguing and most fissile today is between the Runnymede Tories and those Conservatives who dislike the human rights industry, or the specifically European variety, or intellectual abstractions in general. The left are natural dialecticians. Most Tories think “dialecticians” are the people you phone when the fuses blow.

Why has a significant minority of Conservatives become exercised by the risk to civil liberties, and why now? This generation of Conservative parliamentarians was shaped by New Labour, not the cold war. They watched Tony Blair and Gordon Brown regulate, intrude and nurture the nanny state, often in collaboration with Brussels. They fretted as political ambition was given rocket boosters by technology. The new gods were digital, omniscient, swooping through the stratosphere, recording anyone and anything they chose. In the end, Big Brother had come not in the form of “a boot stamping on a human face” but in gigabytes of data unwittingly given by the citizen.

Related to this is the profound schism within Conservative ranks over the western response to 9/11 and subsequent jihadi attacks. When Blair said after the 7/7 atrocities that “the rules of the game have changed”, many Tories agreed (there are shy neo-cons too, you know). Gove was their natural tribune. In his book Celsius 7/7 he wrote (correctly, in my view): “When a senior law lord such as Leonard Hoffmann can say of attempts to restrain the liberty of Islamist ideologues that ‘the real threat to the life of the nation comes not from terrorism but from laws such as these’, then we know we are living in a land that has still not woken up to the challenge we face.”

Runnymede Tories, in contrast, believe that Blair and his successors have exploited the fear generated by terrorism to curtail rights and augment state power. For them, human rights are both profoundly precious and profoundly British. In 1951, after all, Britain became the first country to ratify the European convention – a text that had been heralded by Churchill and (mostly) drafted by the former Conservative attorney general David Maxwell Fyfe. For Conservatives of this stripe, the convention’s roots, furthermore, lie in the common law of this country and what Burke called the “recorded” rights etched into countless judgments of English courts. They are to be found in the 1689 bill of rights, in Blackstone, and in the work of more recent jurists such as AV Dicey.

There are serious practical barriers to the scrapping of the Human Rights Act, not least the extent to which it is embedded in devolution legislation and the Good Friday agreement. But the technical aspects of the problem are the least of it. A folk memory of Magna Carta has been awoken that will not galvanise every Tory MP but is strong enough to give the government whips Magna Hemicrania (look it up).

As I wrote last week, if anyone has the intellectual firepower to square all the circles it is Gove. He will also need political guile, and confidence that David Cameron will stand by him when things get sticky, which they will. Unfortunately, the justice secretary cannot take this for granted. The manner in which Gove was moved from the Department for Education for doing precisely what he had been tasked to do is one of the worst blemishes on Cameron’s record.

This is precisely the sort of issue that might unite the opposition parties – so that every single Conservative vote will count. As things stand, the Runnymede Tories would defeat any bid to ditch the Human Rights Act with support to spare. That’s life with a small majority for you. Welcome back to reality, prime minister.