Bristol 153 was a single engine fighter design to answer F37/35, which was ultimately won by the Hurricane and which later led to the to the Spitfire.
It did bear more than a passing resemblance to the Saab J19.
The Bristol 153 had a Hercules 1500hp engine and had a speed of 357mph with 4x20mm cannon.
I have wondered in the past as to wether with its compact size and radial engine if this would not have been a good option for an FAA fighter?
Right spec. for this aircraft design, for a four 20 mm canon armed fighter. But not related to Hurricane & Spitfire - their's was the F.5/34 later updated to F.10/35.- for a eight machine gun fighter.
Speed was estimated - and as it was only 25' 3" long with a span of 37' so they may have been handling problems. Moreover the canon, were in under wing pods.
Prototypes for the Boulton Paul designs, supermarine 313, and Westland P.9 were ordered - but due to a lack of money from the Treasury only the Westland was built - Whirlwind.