Paraphrasing Rosa Luxemburg, Hal Draper – the American Marxist thinker and leading figure in the American Workers Party – once wrote that the path to socialism was “a war in which there are necessarily a continuous series of ‘defeats’ followed by only one victory". So from that perspective, waking up in the morning is becoming an increasingly confusing experience for the British left. Corbyn’s election certainly isn’t “the final victory”, but it runs contrary to almost every other experience of the past 20 years, in which the left – inside and outside the Labour Party – has been ridiculed and defeated.

It’s all very different to the evening of 12 May, when about a hundred Labour left activists gathered in Mandel Hall. Convened by John McDonnell, the popular backbencher, the “Left Platform” was supposed to be a means of organising collectively under a Labour government. In the wake of defeat, the meeting rambled for hours. The average age must have been about 60, and, other than a few voices telling McDonnell that he should stand for leader (a move dismissed as impossible for lack of nominators), no-one made any real proposal. By the time that Jeremy Corbyn got up to summarise the meeting, most of the young people in the room had drifted off, despondently, to the pub.

By the time that Corbyn became Labour leader on Saturday morning, sixteen thousand people had volunteered for his campaign – most of them young, many giving up their holidays and free time in phone banks, rallies and events. John McDonnell is now the Shadow Chancellor. The quarter of a million first preferences for Corbyn weren’t just more than double the number that any other candidate received: except for a brief surge in the late 1990s, they are roughly equivalent the total membership figure for the Labour Party at any point since the late 1970s.

The earthquake that is erupting in the Labour Party is perhaps the most profound in its history, and for the old establishment of the party, the culture shock will be profound. Having spent 20 years well-resourced and able to dismiss Corbyn and his allies as fantasists and dinosaurs, the Labour right will now have to adjust to being an internal opposition themselves. Being ground down, getting no credit, moderating your tone, picking your battles, sitting in rooms winning the odd minor argument but knowing that you will be defeated in any substantial vote – an approach to politics which is second nature to most of the left will now have to be learned anew by the right.

But it isn’t just the culture of the former Labour establishment that needs to be utterly transformed. The Labour left, too, must quickly adapt to the realities presented by the Corbyn surge – and doing so will require it to face up to its own limitations. In a period defined by the ascendancy of Blairism, much of the Labour left has turned inwards and onto the defence. Far from focussing on creating a Labour Party social movement, the left has for a long time focussed its energies on internal factional manoeuvre – putting together election slates and winning committee positions, often in the presence of a chosen few. There is a desperate need for a united organisation of the left to back Corbyn’s programme, but it needs to be democratic, accessible and run on the basis of open debate, not chess-playing by experts.

Corbyn’s Labour will lose every battle it fights if it remains on the terrain of the old order. The usual process of consolidation and mobilising – which would traditionally involve taking over as much of the party machine as possible and honing the 2020 election message – will never be sufficient in the face of the all-out onslaught from the present government. If the Conservatives can batter the welfare state into US-style penury witout a serious fight, the electorate will be too demoralised to elect a Corbyn government.

To win, Labour must turn outwards: our election campaigns need to look a lot more like the mass, bottom-up persuasion of the Oxi campaign in the Greek referendum than the 2015 Labour general election campaign: think broad mobilising committees in every neighbourhood, regular family-friendly demonstrations and social and cultural events touring round residential areas, posters and discussions in every college, workplace and street – cutting underneath the bile of the right wing media to reach voters directly. And Labour should do more than just verbally support social movements: it should call demonstrations itself and embrace its allies in social movements, offering them resources and platforms.

The task of winning in 2020 is in fact a task of building a mass movement. In order to provide the core of that project, the Labour left needs to transform itself, and fast. For the hundreds of thousands of new potential activists in need of a home, navigating the labyrinth of the current factions, or being told that they have to ‘know the right person’ in a union or committee, or simply being handed down orders from the leadership won’t cut it. These flaws are recognised by many on the Labour left, and if they remain unaddressed they will become the last revenge of Blairism – a relic of the dark years of the Labour left which leaves us unable to effectively lead.

On Sunday 20 September, a conference will be held to ‘relaunch’ the youth and student Labour left. Modest though it may be – it could attract hundreds, but will inevitably fall short of the scale of attendance needed to reflect the Corbyn surge in its entirety – it represents an important trend. In every union and section of the party, there is now a real need to create organisations that throw their doors open to the new influx of new Corbyn supporters. They must be democratic, focussed on including social movements outside of the party just as much as winning internal fights. Bringing these groups into existence, and getting them to relate to a single united organisation of the Labour left which is independent of the leadership will not be easy, but it is these networks that will form the building blocks of a new politics.