From today, Monday 1 October 2015 it is illegal to smoke in a vehicle with anyone under 18 in it.
Both the driver and the smoker can be fined £50.
The change in the law is to protect children and young people from the damaging effects of secondhand smoke, which can put them at risk of serious conditions such as meningitis, cancer, bronchitis and pneumonia, and make asthma worse.
The law applies to every driver in England and Wales, including those aged 17 and those with a provisional driving licence.
The law applies to any private vehicle that is enclosed wholly or partly by a roof, even when people have the windows or sunroof open, or the air conditioning on.
The law also applies when someone sits smoking in the open doorway of a vehicle.
From today, it will also be illegal for retailers to sell e-cigarettes or e-liquids to someone under 18 and for adults to try to buy tobacco products or e-cigarettes for someone under 18.
