A star-studded cast with David Walliams, David Mitchell, Johnny Vegas, and Sir John Hurt has voiced an animated ad showing how to save a choking baby.

The campaign by St John Ambulance, dubbed The Chokeables, sees the actors play objects that could cause babies to choke - a small princess toy, a chewed-up pen lid, a jelly baby and a peanut.

It comes as new research shows that four-fifths of parents (79%) do not know the correct technique despite more than half (58%) saying that choking is a major fear for them and 40% that they have witnessed it.

Sue Killen, St John Ambulance chief executive, said: "Knowing what to do in an emergency can be the difference between life and death, especially with something like choking.

"We all know how time-pressed parents are so this film makes it as easy as possible to learn first aid - in less than 40 seconds we can all know a skill that could save a life.

"We hope people watch and share the video with their friends and family so more people have the confidence to act in an emergency."

In the film, which will air on television for three months, Mitchell's pen lid asks for the audience's attention.

Vegas, playing the jelly baby, then explains that they are all fed up with babies choking on everyday objects like them.

His character says: "I'm a baby who chokes babies, such a tragedy."

As the jelly baby turns blue, Walliams' lofty princess demonstrates the correct technique on him until he coughs up the peanut played by Sir John.

The recommended manoeuvre consists in putting the baby face down on an adult's thigh, giving up to five back blows and, if that does not work, up to five chest thrusts.

If both positions fail, the advert recommends that parents should call an ambulance.

St John Ambulance's research showed that 53% of parents believe that knowing first aid would help them feel better prepared and less scared.

Among those who said they knew how to save a choking baby, only 29% were aware of the correct recommended technique.

Nearly three quarters (71%) gave the wrong answer when given multiple choice options.

Some 39% of parents said they believed that it is the most important first aid skill to have as a father or mother.

And of those who had seen their baby choke, 77% said it was caused by food, 14% by vomit and 9% by toys.

Other hazards included coins, phlegm, marbles and pen lids.

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