It's every parent's worst nightmare.
You're out and your child, who was happily playing in front of you, has disappeared from view.
You scan around but you can't see your precious one.
Your heart jumps out of your chest as the panic takes hold.
Then you hear: 'daddy!' or 'mummy!' The panic's over and you tick yourself off for not keeping your eye on little Archie or Olivia.
Unfortunately, some children do not return immediately and it is one of the worst possible things that can happen to a parent.
But there are things you can do to considerably increase the likelihood of your child's safe return.
Appearing on ITV's This Morning former police officer Mark Williams-Thomas explains this first thing you need to do immediately after you notice your child is missing.
He said: "So the first minute - what do you need to do? Well the crucial thing, and this is the same throughout, stay where you are. Child disappears, the likelihood is they'll come back to where they last saw you."
In a post on This Morning's Facebook page , which has now been viewed more than 280k times in less than 24 hours, Mr Williams-Thomas, goes on to explain what else parents can do in such circumstances.
He said: "In five minutes, so that period of time for the first five minutes, again, stay where you are.
"Also, you now need to contact the police, you need to contact the authorities. Tell people what your child is wearing. When your child goes out in the morning, write your telephone number on their wrist....
"If your child has a tendency to run off, take a photo of what your child is wearing on that morning. Sometimes we forget what our children wear."
With older children he describes how parents should try to call their missing child on a mobile phone if they have one and also have an ICE number (In Case of Emergencies) saved in their child's phone so a parent or other relative is easy to contact.
