Episode 1 "I-Spy" 　　Episode 2 "International" 　　Episode 3 "Imbroglio" 　　Episode 4 "Indecision" 　　Episode 5 "Invertebrates" 　　Episode 6 "Inventive" 　　Episode 7 "Incomprehensible" 　　Episode 8 "Inequality and Injustice" 　　Episode 9 "Illness" 　　Episode 10 "The Inland Revenue" 　　Episode 11 "Infantile" 　　Episode 12 "Illumination and Invisibility" 　　Episode 13 "Intelligence" 　　Episode 14 "Idleness" 　　Episode 15 "Ice (Christmas Special)" 　　Episode 16 "The Immortal Bard (Shakespeare Special)"