Under the sea in Herm, there's a hidden, delicious treasure, oysters. Only seen when the tide is low enough, Justin de Carteret and his team have been farming them on the island for two years.

Grown in the beautiful fresh bailiwick waters, these oysters are in demand as far afield as Japan.

Last year, Justin and his team farmed one million in Herm, this year they want to make that two million.

In the fourth part of our island-hopping food series - Small Islands Big Flavours - our Channel Island foodie Charlie Frost finds out more about how this expanding business copes with modern demands, the old fashioned way.

Then, from sea to land, island Chef David Hook is on the hunt for the freshly foraged goodies Herm's coastline has to offer, before stepping into the kitchen to cook up a delectable taste of Herm.

Watch as we find out what makes a Herm oyster such precious treasure.