A last-ditch October attempt by Hackney Council to suspend the contentious Silvertown Tunnel was rebuffed by Greenwich Council leader Danny Thorpe.

Correspondence released by Greenwich Council following a Freedom of Information request begins with an October 24 letter urging Sadiq Khan to review the scheme ahead of awarding the contract to its construction to the Riverlinx Consortium.

The letter, which was penned by Hackney’s transport lead Cllr Jon Burke, comes with an offer for other London councils to co-sign.

But Hackney’s overtures were rebuffed by Cllr Thorpe, due to fears over potential press attention such a joint letter from London boroughs affected by the process might attract, and how it might be used by “political opponents”.

A spokesperson for the Stop the Silvertown Tunnel Coalition said: “We in the campaign group were leased in October when the Labour Group, having long failed to oppose the Tunnel, had second thoughts and wrote to the Mayor.

“We are dismayed to learn that the council leader did not take the opportunity to join with other councils and take a tougher line with the Mayor.

“The result is the contracts have been signed. However, we are sure that this tunnel will not be built and we will step up our campaign on the grounds that it will increase air pollution and contribute to greater greenhouse gas emissions and global warming.”

The letter opposing the project was sent to London Mayor Sadiq Khan on the 24 October on behalf of Hackney Mayor Philip Glanville and Cllr Burke, whose local authority has opposed the tunnel since 2015.

It is also understood that Newham Mayor Rokhsana Fiaz and Deputy Mayor of Lewisham Chris Best were also “willing” to sign the letter, according to the correspondence.

However, Greenwich’s Cllr Thorpe dismissed Hackney’s offer to join forces in opposition, despite Greenwich Labour Group calling for a pause and review of the project earlier in the month, pointing out that a letter he had written to Mayor Khan calling for tolling on the Blackwall and Rotherhithe had recently been leaked.

Cllr Thorpe wrote: “Having spoken to colleagues this morning in a number of boroughs, I don’t think that this is the way forward. Within a matter of hours, [a] letter that I wrote…was leaked to the Evening Standard and other media outlets, and used in a number of ways by our political opponents. I’m concerned that any joint letters will be used in exactly the same way.

“We have had a lot of positive feedback from residents and members who are clearer about our position and having secured the first unanimous vote on a river crossings policy in the history of Greenwich Labour Group, I’m keen to stick to our position and await a response to our letter from the Mayor.

“I believe that there is merit in a discussion between all of the boroughs affected to discuss in more detail these issues with City Hall directly, and think that strategy is likely to lead to a more positive outcome for all of us.”