A dad who “broke” his son’s heart has launched fresh calls for “keep clear” signs to be installed across London to help tackle air pollution.

David Smith, of West Hill, wants these to be put in front of kerbside bus shelters to prevent children from inhaling fumes from idling vehicles.

Now he is calling on former Tooting MP and Mayor of London Sadiq Khan, as well as Transport for London (TfL), to take action.

He said: “Travelling to nursery and school is arguably the time of a child’s greatest exposure to outdoor air pollution.

“This can lead to reduced lung function growth during childhood, a higher incidence of respiratory infections, a higher susceptibility to the development of asthma, and deteriorating health conditions in children with asthma.

“Many children spend 10 to 15 minutes every school day, standing by the kerb on a busy road breathing high concentrations of diesel exhaust.

“The 'Keep clear' type road markings in front of kerbside bus stops would significantly reduce the high concentrations of toxic exhaust children breathe.”

The father-of-four prevented one of his children, who is three, from riding his bike around Stockwell Skatepark amid fears of him breathing in “harmful levels of pollution”.

They would travel down West Hill and wait for the 37 bus to Lambeth Town Hall, before walking along Brixton Road, to get there.

However, 47-year-old said they would be walking alongside, standing next to, or riding in lanes of slow-moving or idling traffic.

It was done “for the right reasons”, however, Mr Smith says he “broke” his son’s heart.

Alongside collecting recorded data on air quality in West Hill, he wants authorities who manage London’s roads to take bigger steps in combatting air pollution.

Alex Williams, TfL’s Director of City Planning, said: “London’s toxic air is a public health crisis, and we’re committed to tackling it.

“We’re introducing the central London Ultra Low Emission Zone next year, before expanding it to the north and south circulars in 2021.

"We’re also making our bus fleet one of the greenest in the world, with more than 3000 hybrid buses on our network now and with plans for 240 electric buses next year.

"Ultimately, by 2037 all buses in London will be zero-emission."

Mr Williams added additional ideas to reduce air pollution in London are "always welcome" and he is open to meeting with Mr Smith to discuss his ideas.