New movements in Parliament tend either to gain escape velocity, and spin off to become fully-fledged new political parties, or else collapse back into the ones from which they emerged. At the latter end of the spectrum, one might cite Young England or the Fourth Party. At the former, the SDP or Change UK, as the Independent Group now seems to be calling itself. Which eventual fate will be the European Research Group’s?

The question poses itself for at least three reasons. First, the ERG has grown from a group small enough to squeeze itself into Dining Room A for breakfasts to one large enough to have roughly a hundred Conservative MPs on its mailing list, approximately a third of the whole Parliamentary party.

Second, it has morphed from being something close to a think tank to being something closer to an independent force. How else can one describe a group that now has its own whips, presided over by a senior graduate of the Tory Whips’ Office, Mark Francois?

Finally, it is split – or at least was when the Commons last voted on Theresa May’s deal. The number of Tory MPs opposing it has come down from 118 to 75 to 34. Not all of these are Leavers; they include a small band of Remainers – Dominic Grieve, Justine Greening, and so on.

And not all of the Leavers are ERG members, even if they attend the group’s meetings. None the less, the group has formed the core of the Conservative opposition to the deal. As the choices before the Commons have narrowed, so it has itself divided.

One part thinks that the options facing MPs are now either May’s Deal or No Brexit. That bit contains Jacob Rees-Mogg, among others. Last time round, he indicated that this was his view; then said that he would vote with the DUP none the less, but ended up backing the Government.

Another part believes that the choice may still end up setting May’s Deal up against No Deal, and that the latter is worth holding out for. This is Francois’ take – or at least was when he wrote for ConservativeHome at the end of last month.

To date, predictions of No Deal have proved demonstrably wrong. It is still possible that the EU may yet deliver it over Parliament’s head. But the odds of this happening look very long. None the less, most of the group of 39 would probably oppose the deal in any event.

What they seem to think is that one shouldn’t vote for a bad deal simply because the alternatives may be even worse. This is also where the third member of the triumvirate near the top of the ERG appears to be – namely, Steve Baker.

It is possible that Rees-Mogg, on the one hand, and Baker and Francois on the other, band together again if and when the deal comes back to the Commons, and that the number of refuseniks rises from 39 rather than falls.

After all, the Prime Minister’s decision to hold talks with Jeremy Corbyn – and make a very big deal of announcing them – has enraged a big slice of the voluntary party and disturbed a significant section of Conservative MPs, putting May’s leadership under yet more pressure.

So some of those who left the 39 may return. But it is more likely that others will leave in greater numbers. The probability of May’s Deal versus No Brexit – or a softer one – grows each day. None the less, this core of “Spartans” is, well, Spartan. Most of it will hold fast.

Daniel Kawczynski’s renunciation of the group is a sign of the tensions within it. But as he moves one way, others move the other. Yesterday, Anne-Marie Morris signalled that she might vote for the Brexit Party in the European elections.

The emergence of Nigel Farage’s new vehicle offers a new dimesion to the choice facing the ERG and its allies, just as that of Change UK offers one to the new One Nation caucus, as a likely leadership election this year looms into view – not to mention European elections.

That general elections take place under first past the post is a formidable obstacle for new parties to scale. The Brexit Party will be glancing back to the story of UKIP; Change UK to that of the SDP. Both eventually broke the policy mould; neither broke the party one.

The Conservative and Labour monopoly remains – just about. The 2010 election result was a sign that even under first past the post there are limits to its reach. The tensions of Brexit could are likely to return us to the pre-2017 election era (even, arguably, to the pre-2015 one).

At any rate, expect to hear, in the event of European elections, recommendations of a Conservative-Brexit Party pact. These will doubtless spill over into the leadership jostling that is taking place, with potential candidates being quizzed about their views.

This site was very sceptical about a Conservative-UKIP arrangement. Members of our panel took the same view by roughly 60 per cent to 40 per cent. Our instinct is the same about other versions – wherever they may come from and whatever parties they might involve.

It may be that the ERG rattles along as it is for a while longer. But the position of a group with its own whipping operation is ultimately unsustainable – and undesirable, at least for those of us who believe that the Conservative Party, for all its flaws, offers the best future for Britain.

Either the part of the group first described on this site as the Spartans will escape Tory gravity altogether, and soar off into the stratosphere to take its chances on another planet, or else fold back with a deflated sigh into the all-embracing bosom of Celestial Body Conservative.  History suggests the latter.  None the less, the words of the Speaker loom ominously to mind: “If we only went by precedent, manifestly nothing would ever change”.