Girl on Poster
The girl on the poster is the character that is most described in the beginning of the story. She is probably a model, though it is not explicitly expressed. She is beautiful, situated on a beach as she kneels, her feet apart and her hands in the air. She is described sexually in the poem. She is then brutalized as the people of the town she is hung up on passes by.
TItch Thomas
Titch Thomas is not a known character in the poem, instead, his name is signed on the poster. It is not clear if he is a real person, or an alias, yet Philip Larkin decided to add him in the text. If he happened to be the person that brutalized the poster, he might have been a very frustrated and angry person, as he probably delighted in ruining the poster of a girl.