A city council document states that the proposal would not apply to films which portray historical figures who actually smoked, or those which provide a “clear and unambiguous portrayal of the dangers of smoking, other tobacco use, or second-hand smoke”.

In a study published in the New England Journal of Medicine in 1999, researchers wrote that “more than two- thirds of animated children’s films feature tobacco or alcohol use in story plots without clear verbal messages of any negative long-term health effects associated with use of either substance.”

But Mark Wallace, of lobby group the Taxpayers’ Alliance, said he was dismayed at the expense paid out by primary care trusts to fund such initiatives.

He added: “I would say this is a total waste of time and NHS resources.

“PCTs are meant to focus on healing people, not on arbitrating against thought crimes.

“People have enough trouble getting doctors’ appointments and the treatment they need without taxpayers’ money being squandered on the NHS regulating the cinema.”

A PCT spokesman said: “The PCT’s stance would be exactly the same whether it be a cartoon character or not.

“Therefore, if a new film is produced featuring a character who smokes, the PCT would want this film classified as an 18.

“All films featuring smoking we would request be classified in this way, unless it was depicting the harmful effect it has on people’s health.”