New laws should be checked against a “compassion threshold”, to ensure they will not harm future generations or the most vulnerable in society, a cross-party group of MPs will argue this week.

The Green MP, Caroline Lucas, the former Conservative sports minister Tracey Crouch, and the Labour MP Thangam Debonnaire are among those backing the idea that compassion should play a greater role in decision-making at Westminster.

At a roundtable this week, they will discuss a new bill that would aim to ensure any legislation that came after it “cannot leave the most vulnerable in society worse off” and “does not benefit the current generation at the expense of future generations”.

From rising levels of rough sleeping to the rollout of universal credit, there are a growing number of issues that campaigners believe underline the unintended consequences of policymaking on the most vulnerable in society.

Backers of the idea of the compassion bill say they hope it would allow those affected to bring legal action, as they can when they believe their human rights are being breached, for example.

Lucas said: “I think the beauty of the idea around compassion is that it brings both social justice and environmental justice together. Climate is at the top of the agenda now in a way it hasn’t been for many years, and I think there is a moment of really being able to push for some kind of overarching act to make sure that we don’t benefit the current generation at the expense of future generations.

“Linking to that is the endless facts and figures around poverty and austerity in the UK, and the shocking IFS [Institute for Fiscal Studies] prediction that we’re going to see a 7% rise in child poverty by 2022. There’s just a real question now about why it is that compassion is so lacking in politics, when it is a value that most people say they aspire to.”

The initiative is being spearheaded by a new campaign group, Compassion in Politics, backed by the Equality Trust charity, and Academics Stand Against Poverty, an international alliance of researchers.

Jennifer Nadel, the co-founder of Compassion in Politics, said: “An explosive cocktail of worsening inequality, climate breakdown, and the toxic Brexit debate makes this a deeply troubling and disorientating time for Britain.

“We need a new principle that politicians can unite behind to get us off a destructive path and on towards a brighter future. Compassion can be that principle.” She added that the proposed bill would ensure all new legislation must pass the compassion threshold before being enacted.

Lucas said the toxic nature of political debate, with many MPs reporting threats of violence, had also prompted her to think there was an urgent need to find a way of doing things differently.

“The hatred and the anger and the fear – it feels like those things are at their peak at the moment, and our politics is hitting a real rock bottom, for the want of a better word, in a spiritual way as well as a physical way.”