Sunday school

 is an informal form of schooling that takes place on Sundays. (TV: The Evil of the Daleks, PROSE: The Eleventh Tiger) In the United Kingdom, A Sunday school is an educational institution often (but not always) Christian in character.

Sunday school was the only form of education Gwyneth received. (TV: The Unquiet Dead)

Ian Chesterton was taught the Ten Commandments by Father Michael at Sunday school. (PROSE: The Eleventh Tiger)

When Clara Oswald was young, she attended Sunday school with "a nice lady teacher" in a small church room that smelt of oak polish and had felt-tip colouring on the walls. (PROSE: Into the Nowhere)

Graham O'Brien also attended Sunday school when he was a little boy, in Chingford. (PROSE: The Good Doctor)