My hon. Friend is, of course, exactly right. We have now been working on this specific plan for several years. We published a consultation for clean air zones in 2015. The fact that emissions from diesel vehicles have far exceeded what was expected has been extremely difficult. The EU regulatory regime did not show effectively what the real levels of emissions were, and this Government have pushed for improvements to the assessment. We have been planning the draft air quality plan for a consideration length of time, and we will publish it just as soon as we can.