Medics will carry out the procedure if a youngster's size is endangering their overall health.
The gastric balloon works in the same way as a gastric band, and reduces the stomach's capacity for food.
It is being used in a 'last resort' trial for up to 15 obese children who have weight related conditions such as diabetes or constructive sleep apnoea.
There is no surgery involved in fitting the balloon as it is passed through the mouth and inflated in situ whilst the patient is under anaesthetic.
Experts say that if the trial proves successful, it could be widely used across the NHS to cope with the obesity epidemic.
The balloon has to be removed after six months, and the youngsters will be monitored for two years to help them keep the weight off.
Do you think this is a good idea?
Or should more time be invested in educating parents so their children do not become obese in the first place?