After a month of grieving over a devastating defeat, it’s time for the Labour party to stop mourning and organise. The next Labour leadership team must not junk our values, or abandon plans to deal with the big challenges of the age. Instead we must plot our path to power, then deliver it.

Clearly, we wouldn’t have won the general election if we were a bit more leave or a bit more remain. But we have to accept that our failure to respond effectively to Brexit is at the heart of our defeat. If we’re honest, we either wished leaving the European Union would happen quietly and then go away, or we actively tried to change people’s views on the referendum result.

Neither approach was ever going to build an inclusive national mission powerful enough to counter the twin slogans of “Take Back Control” and “Get Brexit Done”.

The Conservatives and Vote Leave transformed the technical issue of our relationship to the EU into a promise of national renewal, by attacking both the political system and our country’s diversity.

Instead of winning procedural games in parliament, we should have used the aftermath of the referendum result to go around the country, holding public meeting after public meeting to stir up a movement for real change – pledging to take on the political establishment and raise up the people’s demands beyond our institutional arrangements with the European Union. That way, our manifesto could have become a set of popular remedies to deal with the three linked crises our country faces: of democracy, the economy and the environment. A joint agenda could have brought people together. Instead, we tried to compromise between the two extremes on Brexit, neither of which could deliver the change the British people need.

Proper democracy takes power away from the offshore bank account and places it on the ballot paper

For lasting, serious change to happen, people in this country must themselves take charge of politics through a democratic revolution. To win again, Labour must become a force capable of bringing that about. Proper democracy takes power away from the offshore bank account and places it on the ballot paper, so workers can have more, and bank accounts in tax havens less, and we can tackle the climate crisis with a green new deal that unites all of Labour’s heartlands.

The people of this country can do it. We can take charge and build a very different future for ourselves, but only if we grasp our most powerful collective weapon: a government for and by the people. We need a popular movement to turn the British state against the privatisers, big polluters and tax dodgers that have taken hold of our political system.

The Labour party now has four years to reconnect with the people of our country, build a powerful movement to raise up their demands and be the force that helps them take charge. Politicians themselves will never upend the political system in the interests of the many, not the few, but our movement can help the people of Britain make that change.

To meet that demand, Labour must continue to change, trust its members and be so much more than a group of politicians in parliament. Much of Labour politics should take place far away from Westminster, as a movement helping people take charge in their workplaces, homes and communities. In this way, we will develop and win support for policies that start a democratic revolution to take power out of the hands of unaccountable elites.

So, yes, that means scrapping the House of Lords. But that is only the beginning. The British state needs a seismic shock, to prise it open at all levels to the people – their knowledge, their skills, their demands.

For the people to take charge, those that hoard power – like the big corporations that fund the Conservatives or the corporate lobbyists who write laws to suit their paymasters – will have to be forced out.

And we have to be honest. For the people to take charge, we must pick a fight with the political establishment. To be trusted, we must show voters how our movement can, and will, win with them.

That’s our path to power.

• Rebecca Long-Bailey is the Labour MP for Salford and Eccles and a candidate for the Labour party leadership