The Liberal Democrats’ London mayoral candidate, Caroline Pidgeon, has proposed plans to ban small and medium-sized diesel vehicles as well as double-decker buses from the London congestion charge zone by 2024.

Before this date, these vehicles would be hit with the “immediate” introduction of a £2.50 surcharge to enter the congestion charge zone.

If elected, Pidgeon said she would also roll out the Ultra Low Emission Zone in 2018, rather than the planned 2020 introduction.

Pidgeon said these changes would reduce the number of people who die from the effects of poor air quality in the capital – estimated to be 10,000 a year.

The Lib Dem politician said she would use City Hall’s “buying power” to bulk-buy a large number of electric taxis, which would then be leased to existing black cab owners, while minicab drivers would be told to convert to low-emission vehicles which are not powered by diesel.

Pidgeon added that this buying power would also help van operators move to electric, hydrogen or petrol vehicles, while London’s fleet of buses would be converted to run on electricity.

The odds of Pidgon winning the election currently stand at 100/1.

“While the current Tory mayor seems content to wait until 2020 before taking any action, Liberal Democrats believe urgent measures are needed now to improve air quality across the city,” she said.

“Because it is a public health crisis, I am planning a highly aggressive programme of improvements that serves due notice to consumers and manufacturers that by 2020 we expect to restrict central London only to those vehicles that have zero or near-zero tailpipe emissions.”

“Transport for London have already said that the vast majority of traffic entering central London will meet the Ultra Low Emission Zone standards by 2020 so there is scope to bring forward the start date of this zone,” Pidgon added.