Shuck the oysters and remove from the shells. Drain the oyster juices and keep in the fridge until ready to use. Sterilize the shells by boiling them in water for 10 minutes, cool under cold water, drain, and wipe dry. Save them for the presentation of the dish.
Blend the cucumber, gin, oyster juice, lime and verjuice to a fine puree. Adjust the acidity and season and to taste.