London Council: "Bio-methane is our preferred fuel source and we have considered the 'source-to-tank' regime as it is more environmentally friendly..."

By Debbie Wood, Business Car. 

Following in the footsteps of Camden Council, which introduced a ban earlier in the year, the 300-strong fleet will be replaced with petrol and hybrid alternatives, once current cycles have come to an end. Only a few diesel vehicles will remain, such as tractors, where there's an operational necessity and no other fuel type available.

Chris Bell, head of procurement, said: "The City Corporation takes air quality extremely seriously. We are taking responsibility for the cleanliness of our fleet and encouraging the use of low- and zero-emission vehicles with our partners," he said.

Across the UK as many as 40,000 deaths a year are attributed to outdoor air pollution, 9400 of which are linked to premature deaths in the capital. The Institute for Public Policy Research, which is urging London mayor Sadiq Khan to ban all diesels in London, says road transport accounts for almost 15% of the total emissions in London.