It was easy to miss amid the media circus surrounding the result of the Labour leadership contest on 12 September, but the Environment Secretary somewhat bizarrely chose that day - a Saturday - to launch her Department's air quality consultation.
This consultation - forced on the Government by a Supreme Court ruling in April requiring it to draw up plans by the end of this year to meet clean air targets by 2025 - was in itself a half-hearted response to the air pollution problem affecting so many communities. It sought to pass responsibility to local authorities, without passing onto them the powers or resources needed to tackle the problem.
But now that the VW 'diesel deceit' has been revealed, it seems clear that the consultation is fundamentally flawed. Liz Truss has been silent on the subject since 12 September. It is time she gave it the attention it deserves. Not to treat it as a tick-box bureaucratic exercise to comply with a court ruling, but to embark on a wholesale review of environmental policy which could save many lives.
To give some idea of the scale of the problem: air pollution causes 50,000 early deaths a year. It is linked to heart attacks, strokes, lung cancer and respiratory disease. The World Health Organisation has classified diesel fumes as a carcinogen. Schools are even being forced to close because of the high pollution levels children were being exposed to. The need for action could not be clearer.
Just last year, Defra figures predicted that air quality in parts of London would continue to be over 25% in excess of legal limits of NO2 in 2030. They projected that 28 of the 43 UK zones would breach legal limits in 2020.
But the consultation projects dramatic improvements. Defra is now claiming that just eight zones will be non-compliant in 2020 and that the whole of London will be compliant within 10 years.
So what is the basis for this optimism?
My understanding is that this very positive picture was painted by DEFRA's new vehicle emissions modelling. The Environment Secretary was warned by her own experts that this modelling was based on the assumption that new diesel vehicles will meet EU emissions standards.
Given what we now know about VW and the massive discrepancies between test data and real world emission levels, it now seems obvious that her Department's assumptions on air quality improvements are not only highly optimistic, but are fundamentally flawed. Toxic nitrogen dioxide levels are far higher than previously thought. The current consultation cannot form the basis for a coherent and comprehensive response to the growing air pollution crisis.
And yet the Environment Secretary has failed to act. Her silence is a complete abdication of responsibility. She should be leading an urgent, cross-Departmental response to bring air pollution down to safe levels. Re-doing the consultation and making genuine efforts to engage on air quality must be the first step, for which she will have Labour's full support.