[1] The Heron was a single bay biplane with a metal structure as described above and fabric covered.

It was powered by a 455 hp (339 kW) Bristol Jupiter VI engine driving a two-bladed wooden propeller.

The Air Ministry issued Specification 25/24 to Hawker for a single-seat high-speed fighter landplane and a prototype was ordered for evaluation.

Despite being heavier than the similar powered Woodcock, it was 15 mph (24 km/h) faster and was praised by the pilots that flew it for its excellent handling properties.

[3] Due to little interest from the Air Ministry, only one aircraft was built and it was returned to Hawker after testing.