The phrase "digression by" is correct and can be used in written English.
It is typically used to introduce a brief change of topic within a larger discussion or discourse. Example: "Digression by the speaker often leads to confusion among the audience, causing them to lose track of the main point." In this sentence, "digression by the speaker" refers to the act of the speaker deviating from the main topic or point.
It returned a minute or two later, followed by more hard braking and a digression by Mr. Swig on the need to accommodate the idiosyncrasies of a vehicle in its ninth decade.
The mixture of fantasy, fable, exotic self-absorption and political digression by means of which the narratives of those two novels are expounded - in the first case linked to the newly independent India, in the second to Pakistan under the military dictatorship of General Zia ul-Haq - changed attitudes not only towards the writing of fiction in Britain, but the publishing of it.
THE BLACK VEIL: A Memoir With Digressions, by Rick Moody.
Mr. Pavic's next novel, "Landscape Painted With Tea" (Knopf, 1990; translated by Ms. Prisicevic-Zoric), is partly organized as a crossword puzzle, with alternating sections titled "Across" and "Down". Readers may approach the book chronologically by reading only the "Across" sections, or less chronologically and with more digressions by reading the "Down" sections.
Much of the poem is taken up by digressions occasioned by places or events of the journey, and it is in these that the attitudes and values of the poet and his circle find their clearest expression.
Lucretius's second book deals mostly with atomic motion and compounds, with a large digression inspired by the diversity of life the Earth supports, and so seems to be a book about life.
Sallust's narratives were enlivened with speeches, character sketches, and digressions, and, by skillfully blending archaism and innovation, he created a style of classic status.
("Imagine if you could only see profiteroles out of the corners of your eyes... ") Yes, he tests your patience with his endless digressions, and by endlessly referring to those digressions.
"In the Wake" is a slow exercise in avoidance by digression.
A vital digression was introduced by the Liberal Democrat leader, Tim Farron, candid in exposition of the agonies of a personal dilemma but settling in the end for a pro-intervention view for the sake of refugees fleeing Isis tyranny.
With a mania for diversion, the novelist offered more than 40 pages on the life of St. Ignatius Loyola, a digression supposedly justified by the fact that many of his characters were Jesuits.
