Which British admiral planned the Zeebrugge Raid in 1918?

The British admiral who planned the Zeebrugge Raid in 1918 was Roger Keyes.

Keyes was a Royal Navy officer and submariner who became director of the Admiralty's Plans Division in October 1917. From that position, he developed a plan to attack the Belgian port of Zeebrugge and block the canal linking it to Bruges. German U-boats and light forces based there threatened Allied shipping in the English Channel and the southern North Sea.

The raid took place on 23 April 1918. British forces attempted to disable the harbor defenses, land troops on the mole, and sink obsolete ships in the canal entrance. The aim was to prevent German naval craft from leaving the inland port. Although the operation did not permanently close the waterway, it demonstrated considerable daring and earned Keyes a baronetcy.

John Jellicoe is sometimes associated with the raid because he proposed an earlier version of a Zeebrugge operation. Reginald Bacon also developed related plans. However, Keyes adapted and directed the plan that was approved and carried out, making him the canonical answer to this question.