It is likely that the planned Silvertown Tunnel will emerge from Tuesday’s toxic talk unscathed – but it is rapidly becoming the frontline of London's war on pollution.

The day (July 5) marks the 60th anniversary of the Clean Air Act giving air quality campaigners a chance to air their concerns over London’s filthy environment.

For protesters, the planned £750m tunnel between Greenwich and the Docklands is little more than a huge exhaust pipe blowing fumes into a part of east London already blighted by pollution.

For others, the tunnel is the answer. TfL, for example, argues that freeing up congestion at the notorious Blackwall hotspot while maintaining a lid on Silvertown traffic will actually alleviate the problem overall – although it admits the two portals will become pollution hotspots.

A queue of traffic on the approach to Blackwall Tunnel

Mayor Sadiq Khan used the anniversary to outline a tougher policy on older cars, with an extra £10 levy on top of the congestion charge. He’s also introducing the Ultra Low Emission Zone a year early and he’s creating “clean bus corridors” so the cleanest buses use the dirtiest routes.

Read more Residents of Tower Hamlets and Newham twice as likely to die of lung disease as affluent neighbours

He said: “The scale of the failure to tackle the problem is demonstrated by the failure of the Government and the previous Mayor to meet legal pollution limits. Urgent action is now needed to ensure Londoners no longer have to fear the very air we breathe.”

He made no mention of Silvertown Tunnel and although he has shown no love for the link, he has deliberately let slip opportunities to block its progress , saying that there was still ample time to intervene if that was necessary.

He knows that Silvertown Tunnel is fundamental to the river crossings package for east London where he needs to see significant housing and business growth and requires accessibility to make that happen.

London Mayor Sadiq Khan

Former mayoral candidate and Liberal Democrat Assembly member Caroline Pidgeon has no such qualms.

She said: “These measures are important but they still do not go far enough.

“In addition to the Mayor’s proposals we need a package of other measures, starting with a rapid switch to zero emission electric vehicles.

“It is also vital for TfL to bulk purchase new electric taxis to help drive down their price and then lease or sell them on to taxi drivers and garages.

Read more Campaigners urge Mayor of London to be ‘consistent’ in stance on pollution

“Other policies are also necessary such as dropping plans for the Silvertown Tunnel, which will merely generate more traffic, through to ensuring that the Enderby Cruise terminal only permits boats to use on shore electric power when berthed.”

She is joined by the Campaign for Better Transport which is calling on the Government to abandon its road – and tunnel – building programme and invest in less polluting forms of transport.

CBT’s Bridget Fox said: “The Mayor of London has shown leadership in setting out proposals for tackling air pollution in the capital, other politicians could take a leaf out of his book.

“But even he must carry through his own argument that tough action is needed and match his rhetoric by dropping damaging road tunnel plans, which will only serve to worsen the city’s air pollution problem.”

The background to the problem could scarcely be more grave.

The Mayor released a report, buried by his predecessor, which showed that 443 schools across the capital exceeded legal air pollution limits. Tower Hamlets, home of the smoking Blackwall tunnel, is cited as one of the three worst-hit boroughs.

The City behind London's pollution cloud

Dr Peter Steer, chief executive of Great Ormond Street Hospital said: “Children living in highly polluted areas are four times more likely to have reduced lung function in adulthood, yet improving air quality has been shown to halt and reverse this effect.

“When the UK’s most seriously ill children come to GOSH, we want to ensure that they are not exposed to high levels of harmful pollution and so we are pleased improving London’s air quality is a priority for the Mayor.”

TfL said in its consultation : “Engines work much less efficiently at lower speeds, and vehicles emit greater levels of harmful emissions when driving in exactly the sort of congested traffic conditions we find so regularly at the Blackwall Tunnel.

“As London grows in the coming years, harmful traffic emissions resulting from congestion in the area surrounding the Blackwall Tunnel will worsen unless we build the Silvertown Tunnel scheme, to ease congestion at the tunnel.”