“HE has all the candlepower of a glow-worm. He might once have fitted the role of a deputy manager of a northern friendly society, but is intellectually unsuited to be a minister of any kind.” This was the verdict of 87-year-old Joe Haines, Harold Wilson’s press spokesman back in the day, describing the Labour leader, Jeremy Corbyn, at the height of last week’s “revenge” reshuffle. More Labour frontbenchers seemed to resign than were shuffled.

And it wasn't the most damning critique of the Labour leader either. He was accused variously of being “incompetent”, “vindictive”, “stupid”, even a “liar” – and all by Labour MPs. It was an astonishing sight. This infighting is unprecedented – especially in an important election year. Many Yes voter rather sympathise with Corbyn, not least because of his opposition to Trident. But Nicola Sturgeon and the SNP can scarcely believe their luck.

Labour MPs such as the Shadow Business Minister, Stephen Doughty, were queuing up to resign live on the BBC's Daily Politics. He was joined by the Shadow Transport Minister, Jonathan Reynolds and the shadow Defence Minister, Kevan Jones. It was hard to keep up with the “perpetuashuffle” as it became known.

Though the broadcasters were more than happy to allow Mr Corbyn's critics to ventilate their grievances at length. BBC commentators lamented the Labour leader's apparent prevarication and incompetence with undisguised glee. Yet, every leader has the right to reshuffle his team, and Corbyn was really only trying to make his front bench a better reflection of the views of the parliamentary party as a whole.

But there had been an eruption of synthetic outrage over the sacking of Shadow Culture Secretary, Michael Dugher and then for Pat McFadden, the Blairite Shadow Europe Minister. McFadden was allegedly forced to resign because he had refused to accept that the Paris attacks by IS could be described as “reaping the whirlwind of Western military interventions in the Middle East”, as the Stop The War Coalition had put it.

Or something like that. To be honest, there was so much nonsense being thrown around last week that it was hard to know what was really going on. Corbyn’s side said Pat McFadden was sacked because he had been “serially disloyal”. This further outraged Labour MPs like Dugher who accused Corbyn of abandoning his promises about a “new politics” of open-mindedness and dissent.

And yes, that was a bit of an own goal. Jeremy Corbyn entered the leadership with some naïve notions about running a parliamentary opposition as if it were a discussion group. And that simply is not possible, as the disastrous Syria bombing debate confirmed. You can't have a situation where the leader of the party is saying one thing and the foreign affairs spokesman is saying the reverse.

That isn't open-mindedness but an abdication. Voters need to know what they are voting for in general elections and that means that the leadership of an opposition party must come to a collective view – after internal debate – about matters of state (like going to war), which is supported by members of the shadow government.

This is not some kind of communist thought control, as has been suggested. It is simply how parliamentary democracy works. Of course, if the leader cannot carry the party, he or she must resign. Equally, if members of the shadow cabinet cannot accept the majority view then they have the option of making their case from the backbenches.

There is nothing sinister in all this. Tony Blair never had to indulge in revenge reshuffles because he never allowed vocal dissenters to get within shouting range of his front bench. From the moment he took over as party leader in 1994, he made it absolutely clear that members of his front bench had to support New Labour and go on supporting it.

There were dissidents like the former development minister, Clare Short, but as soon as they started expressing opposition to the war in Iraq in 2003 (which she initially supported), they were out. As indeed was Robin Cook, the former foreign secretary, who was never a dissident but found he could not longer remain in office after Iraq.

And of course politicians can sometimes be more dangerous on the back benches than on the front. The former Tory chancellor, Geoffrey Howe, demonstrated this exactly 25 years ago when he helped bring down Margaret Thatcher. This may explain why Corbyn stopped short of sacking Hilary Benn.

In sacking Pat McFadden, Corbyn was clearly sending a message to the junior ministerial ranks that in future they had to show some semblance of support for his leadership. McFadden, a leading proponent of Syrian bombing, had been disparaging on social media and on the BBC's Westminster Hour about the performance of the Labour front bench, and the leader himself.

Some thought Corbyn should have kept him in rather than out of the tent, to paraphrase Lyndon B Johnson’s pungent metaphor. But he clearly felt that Mr McFadden's micturation was not of sufficient force to require his presence in the front benches. The same did not apply clearly to the Shadow Foreign Secretary, Hilary Benn.

Benn's disloyalty was clearly greater than McFadden's. He had been cheered and clapped by the massed ranks of Conservative MPs for his speech in the Syria debate, which not only defied the Labour leader’s opposition to bombing but also accused Corbyn – in effect – of failing to “do his bit” as a socialist to challenge the “fascism” of Isis. Disloyalty doesn't get much more serial than that.

But had Benn departed to the back benches, he clearly could have been a very significant rallying point for opponents of Corbyn, in a way Pat McFadden cannot. Several Shadow Cabinet big guns had threatened to resign if he were dumped. He could have been a latter day Geoffrey Howe

And so, after nearly three days of negotiation, the deal appeared to be that Corbyn would keep Benn in post provided he stuck to the Labour leadership line on issues like the renewal of Trident. It is not entirely clear that Benn has agreed to this; indeed he has insisted he has “not been muzzled”. He has said in the past that he supports renewal.

But the expectation is that he will keep to himself any doubts he has about the party leader's opposition to the renewal of the nuclear weapons system, the final "gateway" vote on which is expected this year. This was really what the reshuffle was about: returning Labour to its unilateralist roots.

Maria Eagle, the pro-nuclear Shadow Defence Secretary, was moved and replaced by Emily Thornberry, an opponent of renewing the Trident system in the Clyde. This makes her the first anti-nuclear Labour shadow defence secretary since 1988. That was when Neil Kinnock abandoned unilateralism in favour of multilateralism: the policy of negotiating away Trident rather than unilaterally abandoning it.

This is the latest sign of the grassroots revolution that has swept the Labour Party since the summer. The new membership of the party is thoroughly opposed to Trident and no longer prepared to accept vague notions about negotiated disarmament, which is clearly not happening. Many believe renewal of Trident is contrary to the Nuclear Non-Proliferation Treaty, to which Britain is signed up.

So, it was in retrospect a chaotic mini-reshuffle that could mark a momentous change for Labour. Corbyn seems to be making Trident a defining issue for Labour in future and will be urging his MPs to follow the SNP MPs into the anti-Trident lobbies. How many of them follow his lead remains to be seen. But at least they now know who the leader is, however dim may be his candlepower.