Eighteen words, four short lines, and a whole social divide fits inside them. "Holiday" promises ease, but the poem opens with a purpose: "We sit by the sea / to find still ground." The word itself comes from "holy day", a day set apart, and here the day is set apart for a search. People who go on holiday to *find* something are admitting they don't already have it. The poem never says what is unsettled, only that it needs settling.
The phrase "still ground" is the first thing to puzzle over. The sea is about the least still thing there is, yet it is where "we" choose to sit. The ground is what the sea keeps pushing against, so perhaps the idea is that stillness comes from watching restlessness at a safe distance. The verb "sit" is modest and passive, and the plural "we" feels companionable and unhurried. The purpose clause "to find" quietly undercuts that calm, because finding implies effort and a lack.
Then the poem cuts. Line three arrives with no "meanwhile" or "but" and no verb of hearing or seeing: "At the prison, men singing / till ten at night." The grammar changes along with the scene. The first sentence has a subject and a finite verb, but the second is a fragment, "men singing", with no "are" to pin it to a moment. That bare participle makes the singing sound ongoing, something that was happening before the speakers noticed and will go on after. The definite article in "the prison" matters too. It makes the prison a known part of the landscape, as familiar as the sea. The poem doesn't tell us how close it is or whether the singing carries to where "we" sit. The reader has to make the link, and that gap is where the poem does its work.
The sound patterns are subtle. There is no rhyme, but the short *i* runs through the poem like a thread: *sit*, *still*, *prison*, *singing*, *till*. "Still" and "till" are almost mirror images, and the second pushes the first into a different meaning. One word is about motionlessness, the other about duration, about something that will not stop. The long *i* of "find" is answered in the last line by "night". The rhythm is as spare as the diction. "We sit by the sea" has an easy, two-beat lilt. Line two slows down with three heavy words side by side, "find still ground", so the line seems to come to rest as it names rest. Line three is the longest and loosest, and the unstressed *-ing* trails off. The last line, "till ten at night", is flat and clock-like. The precise hour is the most ordinary detail in the poem, which makes it oddly haunting. Judging by that phrase, the singing is sustained and goes on into the evening, long after a casual outburst would have stopped.
The central idea seems to be a contrast the poem refuses to settle. The people who are free to travel have to go looking for stillness, while the men in the prison make sound, voices rising into the night. It is tempting to read the singing as a kind of ground in itself, a fixed point built from voices, set against the holidaymakers' more fragile quiet. But the poem doesn't say so. It doesn't say why the men sing, whether they are heard, or whether the speakers stay to listen. It also offers no comment on the closeness of leisure and confinement, which leaves a faint discomfort for the reader to feel.
That restraint is what makes the poem significant. It is built from two plain observations placed side by side, and it trusts the reader to feel the friction between them. Because it ends on a time, "ten at night", rather than a moral, the contrast stays open. Holiday here is not an escape from the world so much as a place where the world's unevenness can be heard from a seat by the water.