Police officers who attend emergency incidents are polluting Hertfordshire streets by failing to turn off their engines, a county councillor has claimed.

During a debate on climate change, Liberal Democrat Cllr Stephen Giles-Medhurst claimed police officers keep their engines running so their flashing lights didn’t flatten their car batteries.

But as a result, he says,  exhaust fumes are being pumped onto nearby pavements where pedestrians walk.

And he says, it’s just one example of the ‘culture changes’ necessary to improve air quality and combat climate change across the county.

Highlighting a specific example he had witnessed a few days earlier, he pointed to officers from ‘half a dozen’ police cars that had been dealing with an incident on Leavesden Road, in Watford.

The police cars, he said, were there “for some considerable time” – during which they had their diesel engines running.

He said: “There were a half a dozen police cars there. Guess what? They had their lights on. They had their diesel engines on – and running the whole time with no-one sitting in the car.

“I spoke to the police officer and said, ‘did you need to do it?’ – ‘no, but we’re told to. it’s part of our policy, because we can’t run the batteries down’.

“It’s a cultural change we need here – simple things like that.”

Cllr Giles Medhurst raised the practice during a wide-ranging debate on air quality and climate change, at a meeting of the county council on Tuesday (March 26).

Following the meeting, a spokesperson for Hertfordshire Police confirmed that in some circumstances police car engines had to remain running to keep the batteries charged.

“Where appropriate and safe to do so police car engines will be turned off,” he said.

“However, whilst attending incidents which require the use of lights and the considerable amount of electronic communications and mobile data contained within patrol cars, the engines have to remain running or the batteries will quickly run down.”