Extinction Rebellion has urged MPs to back a bill aimed at cutting climate-warming carbon dioxide and restoring the natural world.
Mike Bold, speaking for the group, called on West Ham MP Lyn Brown and East Ham MP Stephen Timms to support the climate and ecological emergency bill - or CEE bill - which would enshrine in law targets to repair habitats and tackle climate change.
It would commit the UK to playing its part in limiting global warming to 1.5°C, beyond which scientists predict worse impacts of rising temperatures.
Mr Bold said: "They are both very traditional, straight down the line, old school Labour and it's not sufficient to meet the challenge that faces us with climate change.
"They need to break out of the box they are used to operating in."
A total of 100 MPs support the bill, including more than 40 from Labour.
The bill includes a citizens' assembly made up of members of the public who would deliberate on green issues and recommend measures to cut greenhouse gases.
Both MPs welcomed the "passionate" campaigning on the issues, but raised concerns over the assembly.
Ms Brown said: "The climate emergency is a terrible threat to humanity and I take it extremely seriously.
"The CEE bill at the moment has little chance of coming to a vote in Parliament, and I’m afraid to say I’m not yet convinced the strong action we need against the climate emergency will be secured by changing the democratic system in the way the bill suggests.
"We can learn from the example of President Biden, who is taking strong action based on his democratic mandate, and work together to secure a Labour government on the basis of a radical green manifesto in 2024."
Mr Bold argued that relying on Labour getting into power was a "big ask".
Mr Timms said he worked with party colleagues to press for legal commitments in the environment bill, which is making its way through Parliament and includes green targets.
He added these included "excellent ideas" from the CEE bill, but as a presentation bill it won’t be voted on in Parliament.
"I’m not convinced about the changes it proposes to the constitution, but it's right to highlight the need for urgent action to tackle the climate crisis; to cut carbon emissions; halt global warming; keep water, air and soil healthy; and restore biodiverse habitats," he said.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here