General Election 2017: Is pollution in London an issue?

Schoolchildren and parents have been calling on politicians to clean up London's air

School has just finished but instead of going home, children stand in their uniforms on a stage asking politicians for help to clean up London's air.

They are standing next to a road which 45,000 vehicles use every day. Many of those are polluting diesels.

When you talk to them, the children are very aware of pollution and what it is doing to them. They worry about the effect it has on their lungs.

Parents stand around and clap and cheer.

Politicians from a number of parties attended the protest in Kennington

This group in Kennington is part of a growing movement where schoolchildren and parents are trying to get the air in London cleaned up. I have filmed groups in north London, in Soho and in Kennington.

All of them say they do not feel they are being listened to and will not vote for parties that don't take this issue seriously.

So what is different now?

Well these children in Kennington managed to get Labour, the Liberal Democrats, the Greens and the Women's Equality Party to attend their event and get them to sign up to a Clean Air Pledge.

The Conservatives did not attend the event and as yet the children have not had a response from Theresa May.

The politicians at the Kennington event signed a Clean Air pledge

London Mayor Sadiq Khan says with the ultra-low emission zone (ULEZ) due to charge more polluting vehicles in 2019, he can clean up 50% of the pollutants in the capital's air.

But he says he needs help from central government to clean up the rest.

As yet we haven't seen the manifestos, but Labour, the Liberal Democrats, the Greens and the Women's Equality Party agree that there should be a new Clean Air Act to clean up diesel fumes.

Most want a diesel scrappage scheme. Labour seems to be saying it would be willing to charge dirtier more polluting vehicles to enter polluted areas in cities - similar to the mayor's approach.

As yet, the Conservatives have not mentioned a Clean Air Act and say they would only charge as a last resort.

London's ultra low emission zone will begin in central London on 8 April 2019

Air quality campaigners say that approach is "ineffective" and accuse the Conservatives of not engaging with this issue.

It's also interesting as the previous Conservative Mayor Boris Johnson was an advocate of charging polluting vehicles when he started the ultra-low emission zone policy.

The law will also probably play a part in clean air policy due to the work of the environmental lawyers Client Earth.

They have already taken the previous government to court over its plans. The courts agreed the government's policy was not good enough and it had to put together a new plan.

So whoever wins the election, if their air quality policy is not effective, the lawyers will probably drag them back before the judges.

The founder of Client Earth James Thornton said recently: "We are going to have to oblige the government to do things, not ask them".