The device is strapped around the body and inflates in 0.1 seconds if it detects it is accelerating towards the ground, the manufacturers say.

The Tokyo-based company, Prop, says the product is designed to cushion a fall using two separate pockets of air.

One pocket will be behind the head and the other around the hips. It does not protect those who fall forward.

The airbag has been unveiled at the International Home Care and Rehabilitation Exhibition in Tokyo.

The president of Prop, Mitsuya Uchida, says it is aimed especially at old people with epilepsy, who are very vulnerable to injury.

Japan has a large elderly population with nearly 30 million people over the age of 65. There is a huge market for products to protect and assist them.

BBC