A campaigner for clean air from Sustrans has enlisted the help of Hoxton primary school, St Monicas, to tackle the problem of idling drivers in Hoxton Square.

Sharon Meager, 59, volunteers as a cleaner air champion for charity Sustrans, which encourages people to travel by foot, bike or public transport, and asked pupils at St Monica’s in the square to help raise awareness of air pollution.

Having lived in Shanghai where air pollution can reach such high levels that it is dangerous to go outside, Ms Meager is concerned pollution levels in London are getting dangerously high, but that the issue is not taken seriously enough.

Focusing on Hoxton Square, where some vehicles have been known to leave their engines running for over an hour Ms Meager championed an “anti-idling” campaign.

While she designed and produced air fresheners, which were out to local mini-cab firms as an alternative way to spread the message, the pupils drew posters and made postcards which they too delivered to local businesses.

Ms Meager said the children at St Monica’s were brilliant.

“They decided that the best way to tackle air pollution was to try to explain to businesses why it was a good idea to switch off engines.

“They visited the businesses on the square and asked their delivery drivers to switch off their engines when making a delivery because that small change could make a big difference.

She added: “They were so enthusiastic and full of good ideas.”

Hackney Council has now installed permanent signs in the square stating “Please switch off your engines”.

More than 4,000 Londoners are thought to die prematurely each year because of long-term exposure to airborne pollution.

Heart and lung disease, cancer and asthma are linked to air pollution which is mainly caused by traffic and industry fumes.