Researchers say a simple sniffing test could determine if children have autism, even before they're able to speak.

The Israeli trial found children with autism generated an inappropriate sniff, spending the same amount of time smelling both pleasant and foul aromas.

The results show that the more severe the symptoms of autism, the longer the children inhaled the unpleasant smells.

Researchers believe it could provide a crucial indication for autism in non-verbal children, who are usually diagnosed from the age of two, and help them to receive early behavioural interventions.

Autism is a lifelong developmental disability affecting how people communicate and interact with other people.

The researchers said a sense of smell had a role in social interaction, which could explain its link with autism