After graduating from Cambridge, Cockerell initially
went to work for W. H. Allen and Sons of Bedford as a
pupil engineer, but he soon returned to Cambridge to do
research on radio and electronics. In 1935, he joined the
Marconi Wireless Telegraph Company, working at the
company’s Writtle site near Chelmsford. He worked on
the first outside broadcast vehicle used by the British
Broadcasting Corporation (BBC), and he helped develop
the shortwave aerials that began transmitting TV signals
from Alexandra Palace. In 1937, however, his career
took a crucial turn when he was promoted to head of Aircraft
Research and Development. On September 4 of that
year, he married Margaret Elinor Belsham.