Snuff out that snout if you're a driver in England or Wales, as it's now illegal to smoke in a car that's carrying anyone under the age of 18.
Those caught puffing with children in the vehicle could face a fine of £50, and that's regardless of whether a sunroof or windows are open. The only drivers who will remain exempt are those being the wheel of a full convertible with its roof down.
The ban is an attempt to reduce the amount of children exposed to passive smoking, the effects of which can increase the risk of developing asthma, contracting meningitis and falling foul of cot death. Some 300,000 UK children visit GPs each year with symptoms caused by second-hand smoke.
The Scottish Parliament is expected to follow suit with a similar law of its own next year, and though the law comes into effect from today in England and Wales, authorities are expected to be lenient towards offenders for the first few months until the new rules are widely understood.
Worldwide, smoking in cars with children present is already banned in some US states, such as California, as well as in parts of Australia and Canada.