The Boulton & Paul P.58 was the designation given to a series of designs for a fleet spotter, produced in response to Specification S.9/30.
The specification called for a three-seat fleet spotter, capable of taking wheels or floats. Boulton & Paul produced three designs, in two basic forms.
The first two designs were both equal span biplanes, with staged single bay wings. The P.58 used a supercharged Panther radial engine, the P.58A an inline Rolls-Royce F12 engine. The pilot was located just behind the wing, in a raised location that meant that his head was above the upper wing. The other two crew members shared a single cockpit behind the pilot. The P.58 carried a single fixed forward firing machine gun and a flexibly mounted Lewis gun. These two designs were produced in September 1930.
The third design (the P.58B) was a sesquiplane, with a narrow chord lower wing and larger upper wing. When used with wheels they were given large spats, later reused in the P.64 civil aircraft. The P.58B was offered with either the Panther or Rolls-Royce engine.
In the end none of the designs produced for the S.9/30 specification entered production. Only Gloster and Fairey received orders for prototypes, and both of these designs were superseded by the private venture Fairey TSR.1, which was developed into the famous Fairey Swordfish, which could operate as a fleet spotter or more famously as a torpedo bomber.