This week I faced a grilling from a panel of experts.

I have often spoken before select committees in parliament. And John Humphries on the Today Programme is well known for his no-holds-barred interview style. But these guys didn’t so much conduct an interview as an interrogation!

I am talking about the official spokespeople for Year Six at Wembley Primary School.

They were grilling me on air pollution in front of about 100 of their fellow students and they had done their homework.

They knew that in London 9,000 people die prematurely each year because of air pollution. They knew all about diesel cars producing particulate matter that damage children’s lungs. And they were planning to construct “green screens” to act as a barrier around the hotspots they had identified around their school.

But they wanted to know what government could do. So we talked about the target to ban the sale of fossil fuel vehicles by 2040 and why this was far too far in the future. We agreed an earlier target of 2025 or 2030 would be much better.

It was good to know that most pupils had walked or cycled to school that morning — a real change from a few years ago. The students had even proposed their own solution: to close East Lane for part of the day and divert the traffic down a narrow neighbouring residential street — and before residents in Clarendon Gardens start writing to me; Please Don’t! I did explain why that just would not be a great idea.

Our discussions led us on to consider a scrappage scheme with an incentive of a couple of thousand pounds payment to people to trade in their old polluting vehicles to buy a new one with zero tailgate emissions.