Ketamine could offer hope in the fight against cancer, scientists believe.

Promising laboratory tests showed the horse tranquiliser-cum-party drug could kill tumour cells.

Experts think it might block a receptor which encourages tumours to grow. 

Although not proven to work on humans, the Imperial College London team hope similar results could be seen in further lab studies and among patients.

In-depth studies involving thousands of cancer patients would be needed before ketamine is ever rolled out as a treatment, however, meaning any development is still years away at best.