 Also, a semi-portable pillbox or strong point made of prefabricated panels of plastic armour was made for the Home Guard and was considered as a means of covering the retreat of the commandos at the end of the raid on Dieppe.Recognised for his ingenuity, energy and tact, Terrell was appointed to the staff of the First Sea Lord and promoted with exceptional rapidity to the temporary rank of commander.After the war, Terrell and Glanville received a patent for plastic armour, after the invention was disputed by the manufacturers of Insulphate and applied to the Royal Commission on Awards to Inventors for their work on plastic armour.