A Michelin two-star restaurant in Tokyo is facing a criminal investigation after a customer was admitted to hospital having been served the toxic liver of a puffer fish.

Fugu, or puffer fish, is a Japanese delicacy which can only be processed by specially licensed and trained chefs.

By law, chefs must cut out toxic parts including the liver and skin.

But Fugu Fukuji, a restaurant in Tokyo's upmarket Ginza district, last month served one customer puffer fish liver.

The 35-year-old woman had to be taken to hospital after complaining of a headache and numbness in her lips.

The chef is now facing a possible jail sentence for knowingly serving up the toxic dish