It is now illegal to smoke in cars and other vehicles if someone under the age of 18 is present. It is also illegal for a driver to not stop someone else smoking in these circumstances and the fine for either offence is £50.
This new law applies to any private vehicle enclosed by a roof, even if the window is open, the air conditioning is on, or the smoker is sitting in the open doorway of the vehicle (presumably when it is stationary!).
The laws don’t apply to e-cigarettes or convertible cars that have the roof completely down.
For more information, click here on www.gov.uk