The wave of euphoria (or in some cases horror) that swept over Labour party members and supporters at Jeremy Corbyn’s historic victory is beginning to dissipate, replaced by the dawning realisation of its implications.

Corbyn, the left-wing idealist, is the new leader and the man who hopes to be the next prime minister: his faithful friend and shadow, John McDonnell, is now Osborne’s shadow too.

The new leadership team is taking shape, but without many familiar faces from Labour’s past. Many of those who saw Labour as the party of the middle class and supported Tory-lite policies have chosen not to serve in a Corbyn-led government.

The power balance in the Labour Party has fundamentally shifted. For the first time in generations, Labour has collectively identified itself with the poor, the disadvantaged and the working classes of Britain.

Corbyn, in his speech to the Labour Party conference, said he had been given a mandate to create a “new politics” – “politics that’s kinder, more inclusive. Bottom up, not top down. In every community and workplace, not just in Westminster. Real debate, not necessarily message discipline all the time. But above all, straight talking. Honest.”

And he went on to describe the ideals of the many people, young and old, who have joined the Labour Party since his victory.

“Young people and older people are fizzing with ideas… They want a new politics of engagement and involvement. Many of them are already active in their communities, in voluntary organisations, in local campaigns. And we’ve convinced them now to take a further step and join our Labour Party.

“What a tremendous opportunity for our Labour Party to be the hub of every community. The place where people come together to campaign. To debate, to build friendships, to set up new community projects. To explain and talk to their neighbours about politics, about changing Britain for the better.”

Grass-roots politics, rooted firmly in community life – he could have been talking about the co-operative movement. For it is a grass-roots political movement rooted firmly in communities up and down the country. The “new politics” that Jeremy talks about recaptures the spirit of the Rochdale Pioneers, who understood that – as Stella Creasy of the Co-operative Party says – “in times of uncertainty, we are each other’s greatest hope”.

Ms Creasy pointed out that the Pioneers “were concerned as much for the benefits to the individual, as to the community, of participation, to protect the vulnerable as well as to make a profit.

“They were both entrepreneurs and trade unionists. They used their collective might to take the means of production into their own hands – and make markets work on their terms.”

Power comes to the people through working together to create prosperity for everyone, not just for the few – through building communities and generating the collective energy needed to create a vibrant, growing economy; through collaborating to create socially useful and profitable enterprises, sharing surpluses equitably.

Labour has discarded the Tory-lite policies that have now lost it two elections. But if it is to win the 2020 election, it can’t return to the state socialist policies of the 1970s. It must define a new form of socialism, founded upon the principles of self-help, self-responsibility, democracy, equality, and solidarity. And for this, it needs the co-operative movement. For these, of course, are the principles of co-operation.

There is much to do if the dreams and ideas of those who elected the new leadership team are to become reality. It is not enough simply to reject austerity: policies must now be created that redistribute resources more equitably and promote prosperity for all. It is not enough to pledge to end tax evasion and avoidance: fundamental reform of taxation and welfare is needed, so the rich pay their fair share and the poor are properly supported.

It is not enough to threaten to end tax reliefs for big business: what is needed is a fundamental redefinition of the relationship between government and business so that the interests of small businesses, co-operatives and community initiatives are promoted.

And it is not enough to oppose the proposed abolition of the Human Rights Act: what is needed is a commitment to defend the rights of the poor, the self-employed, the sick, the disabled and the elderly.

The co-operative movement should aim to be at the heart of this.

So how can the co-operative movement ensure its voice is heard? The principal route to improved co-operation between the co-operative movement and the Labour Party lies through an enhanced role for the Co-operative Party.

In his pre-election statement to the Co-operative Party, Mr Corbyn said he wanted the next Labour government in 2020 “to work with you so that we are driven by co-operative principles”.

And the new deputy leader, Tom Watson, said he aimed to “foster a new spirit of support between the Labour Party, Trade Unions and the co-operative movement that recognises we share a political agenda and a common purpose”.

Mr Watson proposed a new Labour/Co-operative Forum. “I passionately believe every manifesto we produce, at whatever level, should have Co-operative Party input,” he said. “The forum would plan joint campaigns and initiatives, helping to re-engage members of the Labour and Co-op parties in the political process and becoming a powerful force for community action.”

The new leadership should be held to these promises. But increased Co-op Party involvement in policymaking will not be sufficient. The practical experience of co-operators will be invaluable in developing realistic approaches to the following flagship policies.

• Renationalising the railways: rather than traditional state ownership, Jeremy Corbyn envisages a co-operative form of ownership encompassing government, employees and passengers

• Reform of the financial sector: widen co-operative and mutual ownership of financial institutions and restore their social purpose

• Addressing the terrible distortions in the housing market: by promoting co-operative models in housing, whether through shared ownership schemes such as those used successfully in Germany, or mutualisation of social housing; or improving tenant representation in the private rented sector

• The rights of the self-employed: by helping them to form networks and co-operative enterprises, giving them greater power to fight for better pay and conditions

• Reform of education: by drawing on experience with co-op schools to help develop a new co-op model for state education involving parents, teachers and local authorities.

It is time for co-operators to relinquish their grief and anger over the disaster that overtook the Co-operative Bank and Co-operative Group, and work with Labour Party members and leaders to establish co-operation as the guiding principle of left politics in the UK.