The Green Party is challenging five UK cities to achieve zero emissions city centres by 2023, as it seeks to force the Government to tackle the public health crisis that is air pollution.

The party’s annual conference is taking place, and its co-leader Jonathan Bartley wants local authorities in London, Sheffield, Bristol, Leeds and Oxford to commit to the plan by the end of 2018.

Mr Bartley will tell the party: “The Government has allowed a public health crisis to unfold right under its nose. Its own plans to clean up our air are so bad they are illegal.

“The truth is we need a rapid transition to zero emissions: electric vehicles, streamlined public transport, and investment in cycling and walking. And we need it fast.

“That’s why today I am proud to launch the Green Party’s Breathing Cities campaign to secure zero emission pledges from five of our dirtiest cities within five years.

“Reclaiming our cities as places to live, work and play. Free from the threat of air pollution.

“Putting in place the infrastructure we need to face the future squarely. A future where the environment is at the heart of all we do.”