School.for.Scoundrels. British comedy film 1960

Don't hesitate: this jolly little movie is pretty much impeccable.
An excellent script, which never falters. And a BOFFO cast of British actors. The quintessential role for Terry-Thomas (tho' "Magnificent Men" is a close second).
But also fine turns from Alistair Sim, John Le Mesurier, Hugh Paddick, Peter Jones. Hattie Jacques does an hilarious voice-parody of Joan Greenwood. Janette Scott is VERY good in a thankless "skirt" role; what a charming personality.