Greenwich Council has been made to release a secret report to Labour councillors about its backing for the Silvertown Tunnel under freedom of information legislation, after nearly a year of refusing to publish the information.

The document reveals that Greenwich’s Labour councillors decided to back the Silvertown Tunnel proposals with no evidence that it would do any good – and one year on, there is still no business case to back up the council’s claims that building what is effectively a third Blackwall Tunnel will help regenerate the area.

The report was presented to Labour councillors in November 2012, ahead of the launch of its Bridge The Gap campaign, promoting both a road tunnel from Greenwich Peninsula to Silvertown and a new road bridge between Thamesmead and Beckton.

London mayor Boris Johnson wants to build the Silvertown Tunnel, along with a ferry at Thamesmead.

After a request was submitted under the Environmental Information Regulations Act, the council refused to release the report, claiming it would affect “its ability to develop policy out of the public gaze”.

But the Information Commissioner’s Office ruled in November that the council had been wrong to refuse to release the information – pointing out Greenwich had already made and publicised its decision – and ordered the council to publish it before Christmas.

“There is an inherent argument for transparency and accountability in any spending of public money, and the Commissioner considers that this is relevant for a campaign designed to influence public debate on an important subject,” the ICO said.

“Furthermore, whilst the Royal Borough of Greenwich is not bearing the brunt of the costs for the new river crossing it still has significant influence over how the project evolves, and this has serious ramifications for the people in the borough.”

It added: “There is a strong objection to RBG’s position. Evidence of this can be found on-line, such as a petition with over 400 signatories.

“In the Commissioner’s view this shows there is a legitimate public debate around the subject and also public support for learning how RBG reached its position.”

Three weeks ago, almost a year to the day that I submitted the request, Greenwich finally sent me the report by post. So, the first time, here is the November 2012 Labour group paper on the Silvertown Tunnel and Gallions Reach Bridge.

Councillors voted to endorse the report, which outlines how the council planned to campaign for the Silvertown and Gallions Reach crossings, although some have since said privately they feel they were misled by leader Chris Roberts. What striking is how little there is in the report.

The report does not contain a shred of evidence that either crossing will do any good – merely an assertion that “the potential associated with [developable] land [in the ex-Olympic boroughs] can only be realised by investment in major transport infrastructure in an acceptable timeframe”.

It also failed to anticipate hostility from local residents – merely saying that “environmental groups against an increase in vehicle crossings are rehearsing previous arguments”.

Furthermore, the report said the council would need to develop a business case for the crossings, and a “conference and/or public meeting” – neither of which happened.

So what did happen to the business case? I asked regeneration cabinet member Denise Hyland at this month’s council meeting.

Her response? “TfL will be required to present a regeneration business case as part of their proposals. However a study has been undertaken by independent consultants employed by the London Borough of Newham, for which the Royal Borough provided data to inform the study, which is now in the public domain and demonstrates a clear regeneration case for a new crossing [sic].”

In other words, Greenwich didn’t bother. But does Newham Council’s report justify supporting the Silvertown Tunnel? Let’s have a look at its cover…

That’d be a no, then.

Oddly, among the few times that Silvertown is mentioned, the report’s potential traffic figures claim it would attract no new vehicles at all – which is optimistic, to say the least, and flies in the face of a body of evidence which states that new roads attract new traffic. Indeed, the Newham report even concedes that new developments will lead to more traffic.

It’s even slightly sceptical about Silvertown, saying it is “surprising that TfL report a higher benefit cost ratio for the Silvertown tunnel than the Gallions Reach bridge”.

So, there is no evidence, and no business case for Silvertown. Its own Labour party members won’t back it, and neither will neighbouring Labour councils.

So why is Greenwich Council continuing to support a policy on Silvertown which can only continue to cause it grief? Answers on a pre-paid Bridge The Gap postcard to the usual address.

Want to help the No to Silvertown Tunnel campaign? The No to Silvertown Tunnel campaign, of which I’m a part, is going to be running a new pollution study over a wider area early in the new year. If you can spare either a) time to help put up and take down tubes on weekdays in January and February or b) money to help fund them, then drop info[at]silvertowntunnel.co.uk a line.

We’re also interested in hearing from local firms who’d like to get involved – tech firm Scale Factory, based in Catford and Woolwich, is our first business backer. There’s more on the No to Silvertown Tunnel website.