The so-called "movement" was a loosely defined and even more loosely organized group of English poets who, in the aftermath of World War II, sought to turn away from the kind of modernism championed by T. S. Eliot and Ezra Pound as well as from the kind of neo-Romanticism represented by Dylan Thomas and (to some extent) by the early W. B. Yeats. The "movement" poets wanted a poetry that was clearer, simpler, more obviously structured, and more modest in its style and subject matter. Larkin was early identified as a figure associated with "the movement," and rightly so.
According to a very fine but anonymous eNotes article (cited below), the "poetic reaction" of the "movement poets"
took the form of formal verse, tightly patterned, as against the free-verse style represented by Thomas. Often they returned to eighteenth century patterns, with the ironic tone that accompanied that verse. The irony was subversive, mocking, often self-deprecating. It was very aware of elitism, inflated language and attitudes. Poetic utterance came as understatement, often tentatively expressed.
Philip Larkin's poetry consistently displays almost all of the traits already mentioned. For example, his very brief poem "Talking in Bed"
- deals with a common, mundane experience
- is written in very plain and straightforward language
- has a clear stanzaic structure (three lines in each stanza, with a predictable rhyme scheme)
- deals with the ironies of relations between people and between people and nature
- is understated
- and ends with a stanza that is both understated and ironic:
It becomes still more difficult to find
Words at once true and kind,
Or not untrue and not unkind.
Notice the emphasis here on both truth and kindness (common but important values) as well as on the difficulty of attaining either in many human relationships, including (or perhaps especially) in the most intimate relationships.