"In 1946 a new company appeared using the name Invicta Cars and they produced the Invicta Black Prince. The company was based in Virginia Water in Surrey, and the Black Prince was designed by William Watson, who had previously worked for the pre-war Invicta car company and had also been responsible for designing the very successful S type for Noel Macklin."
Numbers vary, but it seems that only 16 or possibly 18 Black Prince cars were built during 1946-1950, the company then being sold to Frazer-Nash. Six drophead coupe (convertible) bodies were made, the rest presumably being saloons (sedans).
Surviving cars vary in condition from bad to excellent, if Internet image views are indicative.
1947 Invicta Black Prince Drophead Coupe by Airflow Streamline - photos via deRivaz and Ives site
This car was exported to India. Invicta did not build bodies. Like luxury car makers of the 1920s and '30s, Invicta made only the frame, running gear and the hood, grille and fenders -- coachbuilders completed the work.
Styling is pre- World War 2. The folding top was the three-position type: fully up, fully down, and partial -- open above the driver.
The spare tire resides behind the license plate panel.
1949 Invicta Black Prince 4-Door Saloon - Barnfinds photo
I include this image because it shows a roofline different from that of the car in the following photos. Like the drophead in the previous images, this design is prewar style.
c.1946 Invicta Black Prince - photo via Invicta Car Club
Now this Invicta is elegant! And not strongly prewar. The front is the factory design, though the grille bars have a slight "shovel-nose" curve, unlike the drophead's grille.
Abaft of the cowling/firewall, the six-window fastback styling is similar to several late-1930s-early-1940s American cars as well as such designs that were carried over in production after the war. So this Black Prince is in tune with its time. I do not know the name of its coachbuilder.
High rear-quarter view. That oval backlight window was a mistake: at odds with the rest of the otherwise fine design.