Half a million pounds is up in the air after councillors agreed to renegotiate a deal with TfL over the controversial Silvertown Tunnel.

The go-ahead for the Silvertown Tunnel was given by the government yesterday, but last night (May 10), councillors decided not to sign a local agreement over the road.

The deal, which sets out benefits for the borough that TfL would pay for, came under fire by councillors Stephen Brain and Aidan Smith at an extra-ordinary meeting last night.

In the local agreement, TfL had agreed to pay £41,036 for bio-diversity offsetting and £349,500 for “neighbourhood enhancements”.

The Council had negotiated £933,000 for a noise barrier along Siebert Road, but this is no longer necessary as the Government included it in the agreement made yesterday.

Peninsula Cllr Stephen Brain, who has opposed the tunnel in general, said: “This is seriously under-funded in all areas. It is mitigation on the cheap. The funding is not proportional to the scale of the £1bn project.

“The financial contribution for road safety is £136,000 over four years – I thought I missed a nought off this when I first read it. The average pay for a crossing warden in London is £18,300 – basically if we employ just two wardens a year, that’s the budget gone. It’s inadequate.”

Councillors were told that traffic, the environment and other “possible negative effects” would be monitored for  for three years before, and three years after, the scheme is underway – however Cllr Brain said only reacting after problems arose was not good enough for residents.

Cllr Brain said more residents, such as those in Tunnel Avenue, would need a noise barrier, and more should be done against light pollution and to tackle the “diabolical” air quality.

He added: “All budgets are totally inadequate, they appear to be figures plucked out the air – I want TfL to come back with revised mitigations, including roads with sound and light pollution barriers.”

Cllr Chris Lloyd said this was an opportunity to bind TfL into giving extra cash for the Angerstein Roundabout – and voted to renegotiate the deal.

The decision to renegotiate with TfL will not stop the tunnel being built, as the Government has already agreed to that – meaning that TfL can go ahead without the council’s backing.

Newham, on the other side of the river, has failed to reach an agreement with TfL and as it stands will receive no additional cash for the scheme.

There are also other measures included in the deal that are not costed, such as including the London Living Wage for workers on the project, training and jobs and trialling a cycle shuttle bus service.

Pippa Hack, Director of Regeneration, Enterprise and Skills, argued that the council had negotiated a good deal on top of mitigations that were set out by the Government yesterday – and going back to TfL at this point and asking for more could risk losing what had already been agreed.

Chairing the meeting, councillor David Smith said: “If we don’t go ahead with the agreement as it is now then we risk getting nothing. We have half a million on the table, if we say no – there’s a possibility we get nothing at all.

“We find ourselves in quite a difficult situation. There is no doubt in my mind that the measures are not proportionate to the scale of the project, and it’s disappointing we are scrabbling around for small bits of money.

“We haven’t been ambitious enough in the process, the consultation on this hasn’t been good enough. I don’t like turning down money for Greenwich residents, but we shouldn’t accept inadequate support.”

Councillors Chris Lloyd and David Smith outvoted Geoffery Brighty to send the agreement back to TfL without signing it.