A cross-borough plan to manage north London’s waste took a big step forward on Thursday as Haringey became the last council to rubber-stamp the scheme.

The North London Waste Plan (NLWP) is an agreement between seven boroughs that aims to ensure they are able to process the waste they produce up to 2035.

Under the scheme, Barnet, Enfield, Hackney, Waltham Forest and Haringey have identified sites that would be suitable for the construction of a new waste plant.

Waste development could also take place in the other local authorities signed up to the scheme, Camden and Islington, even though sites have not been earmarked in those boroughs.

The site put forward by Haringey Council – Pinkham Way, near the North Circular Road – has led to controversy due to its importance as a conservation area.

Enfield councillor Yasemin Brett, who represents the nearby Bowes ward, was temporarily suspended from the council’s cabinet after she expressed opposition to the inclusion of the Pinkham Way site in the plan at a meeting in November.

At Thursday’s extraordinary full council meeting in Haringey, campaigners from the Pinkham Way Alliance urged councillors not to include the site in its submission to the North London Waste Authority.

The site has been designated a site of importance for nature conservation, and PWA chairman Stephen Brice told the meeting it was home to rare species such as slow worms.

He said: “This Labour council appears out of step not only with its own planning policy, but with the Labour Party’s own biodiversity policy.

“In its paper Green Transformation, the Labour Party sets out its concerns about the UK being one of the most nature-depleted countries in the world and concludes ‘that is why Labour takes the issue of biodiversity decline seriously’.”

Liberal Democrat councillor Cllr Sakina Chenot called on the council to reject the inclusion of the Pinkham Way site and allow the other boroughs to go ahead with the waste plan.

She said: “There are 1,500 trees on the site, and they absorb some of the very high pollution from traffic on the North Circular.

“None of the other boroughs are offering conservation sites. We do not have to – Pinkham Way is surplus to requirements.”

But council leader Cllr Joseph Ejiofor warned that if Haringey did not approve the submission, it could set back the whole project – which has already been six years in the making – putting under threat north London’s ability to manage its waste.

All of the other north London boroughs had already signed off the scheme, and Haringey’s approval was required to move the NLWP on to the consultation stage.

Cllr Ejiofor said: “Every local authority has a statutory duty to be self-sufficient in waste disposal.

“We need to manage the waste we generate in North London. The council has to take a big-picture view on how best to dispose of our waste.”

Cllr Ejiofor added that there was no current plan for a waste facility at Pinkham Way and any proposals would first have to be approved by the council’s planning committee.

He also confirmed that an incinerator would not be built at the site, and that Pinkham Way would only be used for recycling, composting or waste transfer if a decision was made to bring it into use.

Cllr Chenot’s amendment was voted down by Labour councillors, who approved the original motion to include the site in the NLWP in the face of Liberal Democrat opposition.

The decision means the waste plan will now go out to a full public consultation.