On Monday, for the first time in weeks, Brexit was not at the forefront of Westminster’s political minds. Instead, the looming spectre of the UK’s imminent exit from the EU was eclipsed somewhat by the dramatic exit of seven MPs from the Labour Party. 

When Luciana Berger, Chuka Umunna, Gavin Shuker, Angela Smith, Chris Leslie, Mike Gapes and Ann Coffey announced their plan to split, they cited Jeremy Corbyn’s “betrayal” on Brexit and described the party as “institutionally anti-Semitic”.

From Berger’s very first words, the sheer gravitational pull of being in the Labour party was still evident. “I’m the Labour Member for…” she began, before quickly correcting her political Freudian slip and confirming the worst kept secret in Westminster.

But it was the testimony of the less high profile MPs in Monday’s grouping which will have perhaps struck even more of a chord with many of their former colleagues not present. 

Angela Smith got to the heart of the problem with Corbynism, as viewed by many in the PLP (Parliamentary Labour Party), which is that her leader and many around him are privately educated, middle class types who both “patronise” the poor and fail to understand working class aspiration. 

Smith’s barb that Corbynistas see poverty as a “state of grace” is shared by many Labour MPs who see Jeremy Corbyn as nothing more than an ageing student activist. And it was no coincidence that Smith and others today name-checked former Labour PM Harold Wilson. Wilson once said of left-winger Tony Benn (the second Viscount Stansgate) that he was “the only man I know who immatures with age”.

Smith, who like Mike Gapes grew up in a postwar council house before benefitting from Wilson’s higher education reforms, was withering about the class and cultural disconnect between Corbyn and many Labour voters.

The anguished testimony of Ann Coffey, another of the less famous of today’s Independent Group MPs, will be seen by the PLP as all the more powerful, precisely because she is not a shouter or a headline grabber. A former social worker for decades, she cannot be described as a careerist or member of the special adviser cadre that gave Blairism a bad name. 

Yet the presence of Coffey was also a reminder that aftershocks from the twin earthquakes of 2016 – of the Brexit vote and Corbyn’s landslide reelection as Labour leader – are still being felt to this day.

Few remember that it was Coffey who joined Margaret Hodge in co-tabling the motion of no confidence in Corbyn days after the 2016 referendum, a motion that triggered the abortive coup’ by shadow ministers. In some ways, Coffey quitting the party today may mark the end of nearly three years of that particular internal struggle.

Back in 2016, in their letter to fellow MPs, Coffey and Hodge declared that Corbyn’s lacklustre campaigning in the EU referendum had been disastrous. They also said he was the wrong person to win back Labour heartland voters who had fled to UKIP and Leave. 

But that brings us to a major difficulty for today’s independent group. Corbyn will argue he actually won back many UKIP voters in the 2017 election, voters who thought stopping Tory austerity was now the pressing issue.  

Many Labour MPs will emit a hollow laugh at Corbyn’s reaction today (he repeated he won the largest increase in the party’s vote since 1945), stressing he failed the basic leadership task of winning that Blair and Wilson so clearly carried out. Yet the fact is that Corbyn can say he increased votes and seats in 2017. The “security/patriotism” concerns were aired at that election and any voters still backed him.

The other problem for the new grouping is that Corbyn can counter that he rather than they is the one in touch with working class Labour voters’ determination to get out of the EU. 

The breakaway MPs also have to deal with the contradiction that they believe politics is about power not posturing, yet their actions risk keeping the Tories in power while they are themselves reduced to a tiny rump of backbenchers with as much clout as the Lib Dems. 

Some of them will argue that if other MPs join them they can build a group that exploits the hung Parliament as effectively as the DUP has. The danger is they undermine rather than boost the second referendum cause within Labour, as only Corbyn can make it a reality. 

The charge of antisemitism is much tougher for Labour to ignore than the Brexit trigger of today’s rebels. Berger’s resignation may mark an irreparable split with the Jewish Labour supporting community. Already the Jewish Labour Movement is considering whether it has a future. For many worried about bullying and abuse on this issue, John McDonnell’s bank manager mask slipped recently when he told Berger she could stop her local party confidence votes by staying in Labour. 

There is also a hard truth to what many of the seven ex-Labour MPs said today about their former party. It is no longer that party they joined. Its leadership, party HQ, ruling National Executive Committee and membership have all shifted leftwards.

Ever since Corbyn was first elected, his critics have been split over how to respond. Gavin Shuker was one of those who felt in 2016 the leadership challenge was too early, that Corbyn should be allowed to fail on his own terms. Some felt that the longer he was allowed to stay, the longer it would take to rid the party of Corbynism itself.

And thanks to a change in party rules that puts the membership in charge (and makes deselections easier), Corbynism could be around for many more years to come. Today’s rebel MPs think that the 200,000 new left-wing members will forever have a stranglehold on the party’s direction and its millions of voters will as a result be condemned to Tory rule.

That cold logic of a member-led Labour party, rather than the emotional pain, is what really lies behind today’s divorce.

Still, our electoral system makes life very difficult for small new parties. The fact that the new grouping hasn’t a party, a name or a leader looks ominous. So does their ruling out fighting byelections in their own seats. Chuka Umunna weakly inviting the public to submit ideas to a website felt like him hosting a consumer watchdog TV show rather than leading a party. 

Their supporters will see today’s MPs as the Magnificent Seven of Centrism. Their enemies will view them as the Seven Dwarfs of Sellout-ism. The reality may be they end up as neither. But there will be many other Labour MPs left behind who share their belief that their party is further away from power than ever.