Damage done to children's lungs by second hand smoke "may not be reversible", a health expert warned.
Professor Stephen Spiro, Deputy Chairman of the British Lung Foundation, told Daybreak children's lungs are still growing into their mid-teens, so any damage done by cigarette smoke may well be permanent.
"The problem really is that smoking in cars is extremely bad for children - 300,000 visits to GPs are generated by bad soar throats, ear ache, worsening of asthma and other childhood conditions.
"The lungs in children grow until they are in their mid-teens, so that damage may not be reversible."
More top news
The US first lady travelled without her husband to support the Invictus Games, which were founded by the Prince in 2014.
The Pentagon sent a group of military planes just off the state's coast in a show of force.
Iran says it has successfully tested a new medium-range missile, bringing condemnation from Foreign Secretary Boris Johnson..