Labour MPs have joined a lobby group in an attempt to push Keir Starmer into making nature and climate a key part of his election manifesto. Previous Labour nature policies have been “trite”, MPs have said, arguing that the social justice case for climate and nature needs to be made more clearly by the party. The Labour Climate and Environment Forum (LCEF) launches on Tuesday in parliament and is now signing up MPs, councillors and peers. The group argues “that tackling the climate and environment emergency is an issue of social justice and economic prosperity that should sit comfortably at the heart of the movement as a core Labour value”. Members plan to write open letters to the Labour leadership on environment policy, and organise backbenchers to have coherent messaging. They also want to ensure all policy areas from planning to transport have an environmental agenda. LCEF has already produced some research that found voters warmed to Starmer; after hearing him talk about the environment, people were more than 12 percentage points more likely to think Labour was the best party for the economy. MPs have spoken of frustration at the success of the Conservative Environment Network, a group of more than 150 Tory parliamentarians that has managed to push a coherent message on nature and the environment in the party. Many Labour figures think they should be the natural party of climate, nature and social justice, but have been overtaken in terms of rhetoric by the Conservatives. Helmed by the former Labour policy adviser Paul McNamee, the new group is hoping to do the same for Labour, which has been accused by wildlife and climate campaigners of not having a coherent policy on nature, and abandoning plans for a “green new deal”. Its flagship climate and energy policies have been criticised as weak by the leftwing group Momentum and some trade union figures. MPs who have already signed up include Kerry McCarthy, the shadow climate minister, and Darren Jones, who chairs the business, energy and industrial strategy select committee. McCarthy said that although in general Tory commitments on the environment and nature were “quite shallow”, they had “managed to create quite a noise around it”. She said: “You hear Conservative MPs talking about green issues a lot and I think the danger is with Labour is that we can end up just talking to ourselves and maybe talking internally to stakeholders, without actually going out and making the case to the public.” While she praised Starmer and the shadow chancellor, Rachel Reeves, for mentioning green issues in major speeches last year, she said the environmental message was in danger of getting lost. “When Ed [Miliband] was leading [the party], there was no doubt in his green credentials, but he found he spent an awful lot of time talking about, say, immigration or things without a particularly green angle,” she said. “This is about just making sure that they’re trying to think of better ways to put it across, making sure there’s a buzz around it and that people feel confident knowing what our policies are and what we would actually be looking to do.” While the party has announced some policies such as a publicly owned green energy company, McCarthy admits it has a blind spot on nature. “I think we want to go into the election with a very clear offer, I mean, with the 2019 election, and that was a rush job anyway, we weren’t really expecting it. But the one thing I can remember is there was this whole battle about how many trees we’re going to plant. And it almost seemed like that was the whole nature side of the election campaign.” The party should naturally have a stronger message than the Conservatives, McCarthy added. “We are naturally far better on these issues, because we’re not up against these vested interests. So against this sort of ideological example, the sort of Jacob Rees-Mogg approach, for want of a better phrase, that argument that was against environmental protection, against red tape. And we’re against the nimbyism around things like onshore wind, for example, or solar power.” However, she said: “I just feel like there’s in some ways a bit of a lack of confidence, speaking about it sometimes and this group should help us get out there.” McNamee, who has worked for wildlife organisations including the RSPB, sought advice from the Conservative Environment Network when setting up the group. “Particularly in the climate movement, there’s a recognition that the Conservative Environment Network exists, and they’ve done an extremely good job at keeping net zero and climate at the heart of the government,” he said. McNamee says the Labour group aims to assure the leadership that “climate and nature policies are actually extremely popular with the general public. It’s not this kind of fringe issue that it was once viewed to be.” He added: “The thing about climate and environment is the solution to it is going to sit across several government departments – it’s housing, and it’s planning and it’s transport. It’s going to need a real effort from across government. Climate action is no longer just about addressing climate and environmental impact. It’s absolutely key to the future economy of this country.”