Cannabis offer relief to some people by making pain more bearable rather than actually reducing it, a new Oxford study has claimed.

Using brain imaging, researchers found that the psychoactive ingredient in cannabis reduced activity in a part of the brain linked to emotional aspects of pain.

But the effect on the pain experienced varied greatly, they said.

Oxford researchers recruited 12 healthy men to take part in their small study, the BBC News reported.

Participants were given either a 15mg tablet of THC (delta-9-tetrahydrocannabinol) — the ingredient that is responsible for the high — or a placebo.

The volunteers then had a cream rubbed into the skin of one leg to induce pain, which was either a dummy cream or a cream that contained chilli —  which caused a burning and painful sensation.