Other possible inspirations include Lieutenant Colonel Sir Claude Dansey, the deputy head of MI6 and head of the wartime Z network, who achieved different interpretations of his character from those who knew him: Malcolm Muggeridge thought him "the only professional in MI6", while Hugh Trevor-Roper considered Dansey to be "an utter shit, corrupt, incompetent, but with a certain low cunning". A further inspiration for M was Maxwell Knight, the head of MI5, who signed his memos as "M" and whom Fleming knew well. The tradition of the head of MI6 signing their name with a single letter came from Mansfield Smith-Cumming, who would sign his initial "C" navy-style, with green ink.