Sunday school

 was an informal form of schooling that took place on Sundays. (TV: The Evil of the Daleks, PROSE: The Eleventh Tiger)

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)