Bessie was the Third Doctor's special car with which he used to travel around Earth during his exile as his TARDIS was too unreliable. It was a special car that had many abilities, which surprised his companions.
While using it as transport to reach Recovery 7, the Doctor tricked two men who had stolen the shuttle, General Carrington and Collinson by using his Anti-theft device. This meant that the men were stuck to the car. Later, Elizabeth Shaw used Bessie as an escape from some of General Carrington's henchmen. (The Ambassadors of Death)