Revealing his identity would impose “embarrassment and emotional pain” on the complainant [the mistress who was allegedly extorted], who would bear the burden of knowing it was her who was the source of the information and that she could have avoided imposing the pain and embarrassment on MM by complying with the extortion demand, [Judge] Henry said.
Given the identity of MM is an open secret (as happens with most publicised injunctions) but nobody seems to know or particularly even care who the complainant is, that seems to prove the judge wrong.