What is the main theme of the poem "Anne Frank Huis" by Andrew Motion?

The main
idea of this poem is spelled out at the end. Throughout the initial stanzas, Motion usesof
entrapment and imprisonment. The streets are guarded and the rooms are "sunlit"
implying that the speaker understands that Anne Frank wouldn't want to be in a sunlit room,
she'd want to be out in the sun. These are all things that we take for granted.

In the last stanza of the poem, Motion illustrates the guilt feelings of the speaker.
Anne cannot leave,

as simply as I do, and walk at
ease

up dusty, tree-lined avenues, or watch

or watch a
silent barge come clear of bridges

settling their reflections in the blue
canal.

The speaker illustrates that Anne Frank's simple
wish, of leaving whenever she wants to, is something she was never able to do once she went into
hiding. Motion is illustrating the main theme of imprisonment versus freedom, "one enduring
wish ... / to leave as ... I do, and walk at ease." This is what we take for granted and
what Anne Frank didn't have.