Police are not enforcing a new law that protects children from people smoking in a car, reports suggest.
Since October 2015, anyone caught smoking in a vehicle carrying someone under the age of 18 could be hit with a £50 on-the-spot fine. However, no fines have been recorded yet.
According to the BBC, only three people have been caught committing the offence and all three were issued with a verbal warning.
The clampdown was introduced by the Department of Health after widespread research showed the damage that has been done to children inhaling second hand smoke.
Deborah Arnott, chief executive of Action on Smoking and Health (ASH) told The Huffington Post UK that a lack of fines doesn't necessarily mean the legislation isn't working.
She said: "Making smoking in cars a subject of legislation creates a deterrent and gives children the right to challenge adults who smoke in the car they're travelling in.
"Research by ASH, carried out after the legislation came into force, found 86% of children said they weren't exposed to smoke in cars and only 3% said they were exposed most or every day, so lack of fines is not a sign the legislation isn't working."
However, Nigel Rabbits, branch spokesman for Devon and Cornwall Police Federation, which represents officers, said due to the law being unenforceable the figures were not surprising.
He said: "It is poor legislation that hasn't been thought through and it's very difficult to enforce because you are talking about looking at a vehicle and trying to figure out what's going on inside.
"If you're looking for someone under the age of 18 that's difficult without stopping the vehicle and once the vehicle has been stopped getting the evidence for prosecution is extremely difficult."
Experts believe up to three million children are exposed to smoke in cars. This puts them a risk of serious conditions such as bronchitis, asthma, and infections of the ear and chest.
The introduction of the legislation followed similar changes to make all cars smoke-free and outlaws even those who smoke out of their car windows.
According to the Department of Health, many people are unaware of how harmful second hand smoke can be.
A representative said: "In changing the law we always said the measure of success would be in changes in attitude and behaviour, not number of enforcement actions.
"As with other smoke-free legislation, we expect high levels of compliance with this change that will continue to grow."