The black duck was a MG J2. The car itself is a 1933-era MG J2 Midget, part of the most numerous J-type variant, of which 2,083 were built between 1932 and 1934. The J2 was powered by an 847cc overhead-camshaft four-cylinder engine and became one of the defining pre-war British sports cars.
"The Black Duck" is one of those vintage cars that developed an identity of its own.
Here its competing the the Vintage Sports Car Club Cotswold Trial picking up speed before attackign a muddy climb to clear the section.