Montagu Barnes is the head of DEPRAC and known for strictly abiding by the rules. He shows irritation towards Lockwood & Co. members since they do not follow DEPRAC guidelines closely. He seemingly underestimates the small agency.
Barnes lives at Alma Terrace no. 17.
Barnes had underestimated Lockwood & Co. several times but he was somehow not surprised in every success the team had.  He considered the public's reaction and the state of the government when a revelation was unveiled by Lockwood's team; after which, he would ask Lockwood to keep the truths for themselves at least for the moment.
Later (Book 5), Barnes had warned Lockwood & Co. about his hunch of conspiracy he had been noticing. Although, he had been irritated by the team, especially by George Cubbins, he showed genuine concern. He had observed that somehow Fittes and every department/corporation who benefited from the Problem had been eliminating small agencies by absorbing them, or tearing them through grim methods. Also, Barnes admitted that even DEPRAC had been infested over the years with too many Fittes people that he himself, the leader of DEPRAC, had lost control over the department. (Note: DEPRAC consisted of former agents, from any agency, who had gone too old and lost their Talent. Penelope Fittes had sent her spies through that.)
When Lockwood & Co., from inadvertently to deliberately, confronted Penelope Fittes, Barnes was asked by Flo Bones to aid the team. Barnes had but came when the action was finished. He at least helped in clearing up the mess - confirming that Lockwood & Co. are in the good side and Penelope wasn't, capturing the people involved, and preparing how to carefully deliver a controlled news to the public to avoid unrest.