The intervention followed a study by Imperial College London which found that forcing drivers to slow down and speed up again results in notably more harmful emissions.

England has seen a recent expansion of 20mph limits, with several authorities adopting them as a default limit for residential streets, including Oxford, Bristol, Warrington and Hackney.

Meanwhile in 2015 officials in Edinburgh announced that more than 80 per cent of the streets in the centre of centre would to be turned into 20mph zones.

Luke Bosdet, a spokesman for the AA, said: “The target is to get people driving below 30mph in these areas.

“That’s what the 20mph limit is clearly for, and in that sense as far as we’re concerned it’s working.”

“The problem is a knee-jerk reaction to have these zones everywhere.

“If local residents want them, they should get them, but the big question is whether they are being consulted.

“If they’re not being consulted you’re not going to get adherence.”

AA research indicates the number of accidents on 20mph roads has decreased, but that for those who are involved in accidents, the likelihood of being killed or seriously injured has now increased.