Let’s be honest: not many people will have watched Jeremy Corbyn’s first speech as Labour leader in its entirety. Those who caught glimpses will have had it filtered through, shall we say, not very sympathetic media. So we shouldn’t overestimate the effect of Corbyn’s performance in Brighton.

Nonetheless, speeches help to set narratives, and Labour’s narrative holds promise. Corbyn’s commitment to stand up for self-employed people represents a willingness to depart from “old Labour” comfort zones. This is a genuine opportunity for his promise of a new politics to be more than a slogan.

Tuesday’s speech needs to be seen within the context of wider political trends. Democracy across the western world is in decline, or so we are told. Party membership will dwindle, they say; political disengagement is the future. Rampant individualism means we have become a society of consumers, not voters. We no longer believe in collective solutions to our problems. As governments surrender their power to the markets, the realm of policy is shrinking anyway.

What is happening to Labour is the latest challenge to this assessment – a narrative already disrupted by what happened in Scotland, where the referendum on independence politicised a nation.

The Labour party conference reveals a party in transition, from a technocratic organisation into something else: what, exactly, is still unclear. Many of the delegates were selected early in the year, before the great influx which has transformed Labour. That doesn’t mean their allegiance is to Labour’s old political order. It was, after all, existing activists who handed Corbyn the most nominations of constituency parties.

In an insightful piece last month, Michael Harris, a Blairite former Labour councillor, wrote that there was a new leftwing political party in Britain which was, “for now”, called the Labour party. When he was selected as a Labour candidate in Lewisham, his “local party had 80 (mostly quite old) members”. That number had surged to 250. The new members were “young” and “diverse”, he noted. The party was becoming something else, organically, from the bottom up.

This year’s conference certainly seems younger and more diverse than any I’ve seen, and many in attendance have an infectious, boundless enthusiasm. The danger is that their excitement could dissipate.

Labour faces months of being bloodied by virtually the entire media, and it would be easy to end up feeling impotent in the face of such an onslaught. If Labour has a chance of surviving the merciless attacks that are headed its way, it needs a sophisticated media strategy.

But survival also depends on the grassroots movement that gave Corbyn the greatest democratic mandate of any British party leader in history. In the week following Corbyn’s victory, more than 50,000 people joined the Labour party; 150,000 had joined as members since Labour’s election defeat, and during the contest 100,000 signed up as supporters. It is a remarkable triumph for democratic revivalism. But I suspect they are not joining to while away their time in meetings discussing resolutions, or simply knocking on doors for voter ID.

Britain has, thankfully, not suffered the plight of hyper-austerity-ravaged Greece. But Labour needs to still learn from the Greek experience, from the social movements that emerged before Syriza’s victory, and which played a key role in the party’s triumph. Kitchens, legal aid centres, food banks, soup kitchens and free education classes were set up across the country.

Labour has a similar kind of army – engaged people who are brimming with enthusiasm, rather than simply grumpily opposed to the Tories – and it needs to use them to build a genuine social movement. Why not, for example, start opening food banks – but with a difference? Instead of acts of charity, what about trying to organise those who, in the fifth-biggest economy on Earth, have been left unable to feed themselves.

Britain has up to 11 million private renters, often being charged rip-off rents and deprived of basic housing security. Why shouldn’t Labour set up private tenants’ associations, again to help organise people? The party is talking about the rights of self-employed workers who value their independence, but not the insecurity of those with no pension and limited social security. Why not try to organise them, too?

After the London riots, a young community organiser in Tottenham told me about his strategy to engage with young people. Not with top-down meetings but football matches. Afterwards, he got the players to talk with community figures and politicians about their concerns and ambitions. Youth services are often the first to be slashed by Britain’s hammered local authorities, and leisure activities with a political edge could prove attractive. That’s surely the approach this changing Labour party must have: politics made fun, rather than stale and dreary.

Labour needs to win over older people and combat the threat of intergenerational conflict. Why not set up schemes where young party activists spend a couple of hours a week with older people who lack company? Why not establish community centres offering a diverse range of activities? Social enterprises could be set up.

With the Tories trying to stitch up the electoral system in their favour, Labour must surely begin the biggest electoral registration drive in British history.

By becoming a social movement, Labour could make its already booming membership soar: 1 million members must surely be the party’s aim. But being an active presence in the community is surely more effective than simply knocking on doors. It could win over those who feel alienated from politics. It could attract those voting Ukip because of their unanswered concerns on everything from housing to public services.

Those joining Labour are being patronised and infantilised, the subjects of diagnoses from cod psychologists. But what has happened in Scotland and with “Corbynmania” at least has the potential to be the beginning of a democratic renaissance.

There is a growing well of excitement that Labour can draw on. It should not miss this opportunity, or wait until enthusiasm turns into pessimism. This is not a personality cult in action: Labour has been inflated by people who genuinely want to change things. The future of the party rests on their hope. It would be fatal to squander it.