It was designed by Royal Navy Lieutenant John W. Seddon and A. G. Hackett[1] and built by Accles & Pollock.

Design of the Seddon Mayfly began in 1908, with the intention of attempting to win the prize for a flight between Manchester and London given by the Daily Mail.

[3] It was built in Oldbury by Accles & Pollock, a company who specialised in the manufacture of steel tubing, and its structure made extensive use of intersecting pairs of steel hoops: over 2,000 ft (610 m) of steel was used in its construction [2] The aircraft had two sets of biplane wings, the front pair of greater span than the aft pair.

Control surfaces consisted of a forward-mounted biplane elevators and a pair of diamond-shaped rudders mounted between each set of wings.

These were made of sheet aluminium, with the semi-circular blades supported at the ends by attachment to a radial tube.