Speaking to the crowds at Labour’s 2012 party conference, Chuka Umunna talked about “an irresponsible experiment with people’s lives”. In a powerful speech as the Shadow Secretary for Business, Innovation and Skills, Umunna rightly attacked the Tory government for the human cost of their damaging austerity project. He noted the soaring levels of unemployment, called out the cruelty of cuts and spoke of a better, brighter future under his party. And to the Lib Dems, he said: “You are all in this together.”

Seven years later, Umunna and seven other former Labour MPs have joined forces with three ex-Conservatives. Although they quit their party citing the “firm grip of the ERG” and the need for “compassionate conservatism”, the voting records of Heidi Allen, Anna Soubry and Sarah Wollaston tell a different story. Along with consistently voting in favour of the government’s welfare cuts, they have also supported restrictions on the scope of legal aid and a stricter asylum system, and opposed higher taxes for banks and corporations.

Why does this matter? Can the new Independent Group not put their differences to one side in the national interest? Can’t they move on from the past and work together to fight against Brexit? But ideology matters. It shapes the way we think about the world, society, jobs and rights, workers and equality. It shapes everything we do and everything we stand for. To ignore the role of ideology, or pretend it doesn’t matter, would be to ignore so much of what built some of our nation’s greatest achievements.

You can’t take the ideology out of the NHS because it was built on the founding principles of redistribution and radical reform. You can’t take the ideology out of the welfare state because it was built on ideas of social solidarity and protecting the most vulnerable. A minimum wage, equal rights legislation, Sure Start, employment rights, devolution, the world’s first Climate Change Act – all built on an ideology of fairness, equality and the power of ordinary people.

That these former Tories supported some of the last decade’s most painful, devastating policies matters. The fact that welfare reductions and cuts to housing benefit have plunged thousands of people into poverty matters. And the fact that Allen, Soubry and Wollaston all stood by and let it happen? That matters.

We don’t know what The Independent Group’s future policy platform will be, if they ever reach one. We don’t know how many more MPs will join them. But we do know that our former Labour MPs rightly stood against the Conservative ideology that has dominated policy-making for the last decade, policy that their now-colleagues supported in the division lobbies. I’m all for consensus-building and collaboration, but ideological divides don’t just dissipate. How long will it be before we see this ‘third force’ in British politics fall fate to the very basis on which it was formed – irreconcilable ideological difference?