The frontline in the battle over Silvertown Tunnel will be barely visible beneath clouds of toxic fulminations.
The forces against the river crossing are gathering around the banner of air quality, which has plenty of momentum, legally, morally and topically.
News that 10,000 people a year die from polluted air in London, twice as many than previously thought, adds weight to the opponents’ cause and makes the task of cleaning up the capital all the more necessary.
Silvertown supporters, notably Transport for London, at least know the terrain on which they must fight.
The argument that idling cars at Blackwall Tunnel create air quality blackspots contends with the presumption that river crossings will only serve to ease, rather than eliminate, congestion in a fast growing city.
So it will be up to TfL to make a convincing case that overall the impacts will be reduced, even if new blackspots are created.
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This is an argument already won in the court of public opinion – 83% of people are in favour of a tunnel – but those arguments will have to convince a judicial review that will be informed by the recent Supreme Court ruling that ordered the Government to step up efforts to reduce NO2 emissions.
One beneficiary is likely to be the Brunel Bridge, the pedestrian and cycle link between Rotherhithe and Canary Wharf (markedly superior in function to the Garden variety).
If only for reasons of political expedience, the Brunel Bridge should be made a junior member of the East London River Crossings package and implemented as one of its quick-win priorities.