Krontonian ambassador

From Tardis Wiki, the free Doctor Who reference

A Krontonian ambassador once lost his seal of authority. The Doctor helped him to find it again, discovering that his son had swallowed it. The Fourth Doctor later recalled this incident as an example of an adventure which was too mundane for the readership of Doctor Who Weekly to have heard about. (PROSE: A Letter from the Doctor 10 [+]Loading...["A Letter from the Doctor (DWM 10 short story)"])