Careful With That Pronoun

From The Guardian (UK) (emphasis added):

The existence of a previously secret injunction against the media by oil traders Trafigura can now be revealed.

Within the past hour Trafigura’s legal firm, Carter-Ruck, has withdrawn its opposition to the Guardian reporting proceedings in parliament that revealed its existence.

UPDATE: Some commenters pointed out that “its” isn’t ambiguous here, and that’s right: On reflection, it’s pretty clear what the “its” must refer to. But you shouldn’t have to engage in such reflection to parse a sentence. (To understand an argument, maybe — but not to parse a sentence.) So even if “its” ends up being unambiguous, it will likely be distracting, at least to many readers.