Not a poem...

Actually, the original published edition (New Directions, 1954) presented it in verse form. Click on the image in this link and you can see the formatting:

http://www.abebooks.co.uk/servlet/BookDetailsPL?bi=1175605433&searchurl=an%3Ddylan%2Bthomas%26sortby%3D1%26tn%3DChristmas%2Bin%2BWales



I've never had my hands on this particular edition, but I've seen the story in verse form elsewhere -- I saw a book version formatted this way, and I've got a magazine called "The City" (an insert in the Toronto Star back in the 1970s) that shows the story as a poem.


The original stories that were combined into what we now know as "A Child's Christmas in Wales" were not in verse form, of course. And I can't recall whether Thomas had anything to do with them being in verse form (the book version was published after his death, of course). I did research this some time ago, but alas, my memory fails me and I'd have to go find that research.


But speaking strictly about the "prose" versions ...

Whether it's a "poem" is a matter of opinion, and it depends on whether you consider the "prose poem" to be poetry. People are divided on that issue.

But "prose poetry" is a branch of literature unto itself, and refers to prose marked by heightened, metaphoric language that one would find in conventional poetry.

"A Child's Christmas in Wales" falls into the category of "prose poetry." The only question is whether "prose poetry" is, indeed, poetry.

Personally, I feel that it is, at least as much as blank verse, which only differs from prose poetry in that blank verse employs arbitrary line breaks that are inserted for no other reason than to make a prose piece look like a poem. Prose poetry simply elects not to engage in such artifice.