The Boulton Paul P.104 was a design for a pusher naval fighter produced in response to Specification N.7/43.
The original version of that specification called for a naval fighter based on an existing design, but Boulton Paul got it altered so that new designs could be considered. The company put forward two designs. The P.103 was a standard type, based on the Defiant, but the P.104 was more radical. It was a tail first aircraft, with a Griffon engine powering a pusher propeller.
The deadline for N.7/43 was 24 April 1943. By May the Naval Staff had decided not to use either of the Boulton Paul designs, and instead went for a lightweight version of the Hawker Tempest, which became the Hawker Sea Fury.