There’s no such thing as a Tory rebellion – as this week in the Commons showed There isn’t much that unites the various warring factions of the Labour Party as far as the United Kingdom’s relationship […]

There isn’t much that unites the various warring factions of the Labour Party as far as the United Kingdom’s relationship with the European Union goes, but they can at least share a laugh at the expense of pro-European Conservatives.

If you have been following the news closely you may have heard from that increasingly derided tribe of politicians: Tory MPs who campaigned to stay in the European Union and think the best flavour of Brexit is one that keeps the United Kingdom as close to the bloc as humanly possible.

They frequently write anguished columns or send sternly-worded tweets about how Theresa May needs to change course on Brexit or they will defeat her in the House of Commons and change course for her.

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Backing off

Then the vote itself comes around, and rather like Macavity, the rebels are nowhere to be found, at least not in the House of Commons. Anyone reading the papers this past fortnight would have been forgiven for thinking they had simply picked up last week’s editions: Tory rebels threatened to defeat the Prime Minister over the terms of the final vote on Brexit, before being twice backing off at the eleventh hour.

The diagnosis, at least as far as the Opposition parties go, is that most pro-European Conservatives are all mouth and no trousers: they are happy to talk about rebelling but when push comes to shove, they fall into line, bought off by the thinnest of concessions.

Parliamentarians don’t like to rebel and most do it rarely, if at all

Of course, pro-European Tories don’t see it the same way. They believe that they have won a series of serious changes from the Downing Street through their actions. As one of their number put it to me, you don’t shoot the hostage once the other side has handed over the money.

Are they right? It doesn’t look like it. Pro-European Tories used to talk of a “soft Brexit” as an exit from the European Union in which the United Kingdom retained its membership of the single market plus a swathe of other European institutions, such as Euratom, which manages the transfer of radioactive isotopes, used for cancer treatments and research, across European borders.

The concessions that pro-European Tories are winning are thin gruel: so do they keep doing it?

Tribal by nature

The answer lies not in the internal character of the Tory party but in human psychology: we’re tribal creatures by instinct and MPs are no different. For MPs, who thanks to our antiquated voting system have to physically walk into voting lobbies alongside their usual opponents, the experience of being isolated from their tribe is not just psychological, but physical, too.

One of Labour’s most longstanding pro-Brexit MPs, who has been rebelling against Labour leaders throughout their long career, once told me that they had still never got over having to share a lobby with the Tory foe.

That urge not to leave the tribe is why Conservative MPs continue to hand over their hostage in exchange for Theresa May’s counterfeit currency

Parliamentarians don’t like to rebel and most do it rarely, if at all. Even Jeremy Corbyn, who before becoming Labour leader was one of the most rebellious in the party’s history, followed the party line more often than not in the House of Commons. (Even in his most rebellious period in Parliament, from 2005 to 2010, he only voted against the Labour line one vote in every four.)

‘Sick and unhappy’

One pro-European Labour MP, who has voted for a closer relationship with the European Union after Brexit regardless of whether it is the Labour line, told me after his most recent rebellion that he still felt “sick and unhappy” after each one. That feeling of isolation is similarly acute among the small group of Tory rebels who actually have turned words into action.

It’s a desire to avoid that fate which encourages rebel MPs, regardless of party, to find as many excuses as possible not to break ranks. The same holds for Labour, too: although Labour MPs have been more likely to rebel, the 50 or so Labour MPs who rebelled to keep the United Kingdom in the single market are at best a third of the total number of Labour MPs who disagree with the party’s official position.

That urge not to leave the tribe and make common cause with their traditional enemies is why Conservative MPs continue to hand over their hostage in exchange for Theresa May’s counterfeit currency. But as always with fake money, while it might feel right in your hand, it might look right, it always ends in tears when you try to deposit it in the bank. The concessions “won” by Conservative pro-Europeans will have a similarly short afterlife.

Stephen Bush is special correspondent of the New Statesman

@stephenkb