A new British law banning smoking in cars while children are present came into effect yesterday but police representatives said it will be “extremely challenging” to enforce.
A driver who fails to stop a passenger smoking in the same circumstances also faces a fine.
The Scottish parliament is considering bringing in a similar law next year.
Sally Davies, the Chief Medical Officer for England, hailed the “landmark” legislation.
“Smoking a single cigarette in a vehicle exposes children to high levels of air pollutants and cancer-causing chemicals like arsenic, formaldehyde and tar,” she said.
The changes follow an experiment by Newcastle University which found levels of dangerous chemicals were more than 100 times higher than safety guidelines when a passenger was smoking.