Intermittently — throughout the whole EU debate — an article I wrote last July resurfaces on Twitter. In it, I argued that the left should consider the case for Brexit and that “at the very least — more of us need to start dipping our toes in the water.” Like others on the left — including Jeremy Corbyn — this is used as evidence that (at best) I secretly support Brexit, that I have changed my mind out of loyalty to the Labour party, or that I’m simply a flip-flopper. The last point causes me some amusement: on the one hand, I’m continually accused of being dogmatic and unbending in my opinions, but when I publicly think through my opinions or change my views in good faith— showing everyone my working as I do — I’m accused of blowing in the wind.

Amusingly, I coined the (awful clunky) term ‘Lexit’: a ‘left exit’ from the EU. This was then adopted as the official name for the left-wing Leave campaign, and those on the left backing exit call themselves ‘Lexiters’.

But it is worth explaining exactly what was going on last July, because I think it has been lost from the history of this referendum, and will hopefully also make people think rather more kindly about Jeremy Corbyn’s contribution to the campaign.

Last July, David Cameron was on course to sign away workers’ rights as part of his EU renegotiation package. As the Guardian reported on 11th July:

David Cameron is to make an opt-out from EU employment social protection laws such as the working time directive and the agency workers’ directive one of his goals in his negotiations with Europe, according to reports from Conservative political sources in Brussels. If the prime minister achieves the demand as part of his renegotiation with his EU partners, it would be a body blow to efforts to persuade trade unions to support British membership of the EU on his new terms.

This was a red line for the left. and for the trade union movement. Workers’ rights enshrined as part of EU membership — like equal rights for part-time and agency workers as well as paid annual leave — now form the linchpin of the left-wing Remain case.

David Cameron had to be forced to back down. A series of discussions took place on the Labour left, with senior Scottish Labour figures and senior trade union figures. The disgraceful treatment of Greece was still very raw and focused minds. But, crucially, if David Cameron believed that the left and the trade unions would blindly back whatever renegotiation he came up with, then he had no incentive to preserve the social aspects of the EU. That, indeed, was his calculation.

So there was a concerted effort by the left to make it clear that support for Remain would not be unconditional: far from it. My own column was a — small! — contribution to this. Two days after it was written, the Financial Times’ Jim Pickard announced that Unite — the country’s biggest trade union — was considering backing Leave “if David Cameron uses his renegotiation with Brussels to weaken workers’ rights.” In addition:

Unions have been among the strongest supporters of the EU, but they believe the prime minister now wants to roll back employment rights first secured in Brussels. They fear he wants to weaken directives on working hours and agency workers, or even restore the UK’s “opt out”over EU employment laws. The Trades Union Congress, the GMB and Unison have all warned that the Yes camp cannot take their support for granted ahead of the referendum.

As the FT additionally — and correctly — added: “Jon Trickett, a member of the shadow cabinet, has joined forces with the commentator Owen Jones to discuss a broad ‘Left Out’ campaign.”

A week and a half later — and just a few days after a YouGov poll made him the frontrunner for the Labour leadership — Jeremy Corbyn made his own intervention. As The Guardian reported:

Asked again whether he would rule out campaigning to get out, the Islington North MP told the hustings: “No I wouldn’t rule it out … Because Cameron quite clearly follows an agenda which is about trading away workers’ rights, is about trading away environmental protection, is about trading away much of what is in the social chapter.

But here’s the crucial point. It worked. As the pro-Brexit former Conservative commentator Tim Montgomerie put it at the end of August:

As the Financial Times summed up above: “Cameron drops demand for full immunity from EU labour rules… Bid to keep unions and Corbyn with ‘in’ camp.”

The left is often accused of strategic incompetence (sometimes, to be fair, for good reasons). But here was an example of the left flexing its muscles and getting results. It wasn’t a bluff (well, certainly not on my part). If Labour figures, the trade unions and the left had not done this, David Cameron’s deal would not have protected workers’ rights. Would this result have been achieved without the Jeremy Corbyn surge? I’m not so sure. And — given how close the polls are now — it would surely have guaranteed Britain’s exit from the European Union. That may happen anyway — and everybody on the left should realise that there is no Lexit, only an exit on the terms of the right. But, whatever happens, history should accurately record the left’s contribution to the referendum.