Dear Mayor Khan,

As parents, grandparents, aunts, uncles, guardians, carers and teachers, we urge you to please cancel the Silvertown Tunnel.

Nothing matters more to us than the health and wellbeing of the children we look after. We believe that the effects of the Silvertown Tunnel will reduce their quality of life in all manner of ways.​

It would be an act of significant political courage to do so. But it is also the right thing to do on the grounds of public health and wellbeing – and we will credit you for it.

Why cancel the Silvertown Tunnel?

First, it will harm our children's physical health.

Lung development in children depends upon clean air, but local air quality is highly likely to worsen as a result of additional road capacity being added in this part of London, as it will funnel new traffic including heavy goods vehicles (HGVs) through our area, attracted by the tunnel's dedicated HGV lanes.

The longer-term adoption of electric vehicles is no solution either. Up to half of air quality damage is attributable to tiny particles from tyre wear and brake dust rather than exhaust fumes. These are the type which are most harmful to human health and affect every part of the body because they enter the blood stream.

Schools with the poorest air quality at the moment are liable to be hardest hit, particularly those in Greenwich and in Newham (which is already the most polluted borough in the UK).

Second, it will lock us into polluting infrastructure.

We are in a climate and biodiversity emergency.

The scheme is completely contrary to encouraging the social changes required to engineer an 8-9% reduction in greenhouse gas emissions year on year.

The only realistic effective changes to infrastructure happens at the point of design. Once damaging infrastructure is in place, it is almost impossible to dislodge it.

It is inconceivable that constructing this road tunnel will not add vehicle fuel to the climate firefight we find ourselves in. Our children will not forgive us for not trying to halt such damaging projects.

Third, it will not alleviate the problems even on its own terms.

Congestion is likely to be temporarily alleviated before worsening, and in some places such as the A2 south of the river during peak hours it will be considerably worsened.

The empirical literature is clear that road construction incentivises car driving and further takes us away from the low-car infrastructure that the city really needs.​

It is perverse that the business case for the tunnel indeed relies upon this increase, since the tolls paid by drivers will be how the private finance initiative (PFI) contract debt is repaid.

We need river crossings in this part of London, but not road tunnels. Silvertown Tunnel is the wrong kind of infrastructure investment to be making to achieve targets for more active travel.

It is not too late to revisit the Silvertown Tunnel greenlight and call a halt. We urge you to do so, in all haste.​