Update: Trudeau has named Carla Qualtrough, currently the minister of public works and government service, and will make a comment about Philpott's decision to leave the cabinet Monday night.

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So much for "circling the wagons".

One of Prime Minister Justin Trudeau's most trusted ministers announced on Monday that she planned to resign from his cabinet following damning testimony last week from her close friend, former Justice Minister Jody Wilson-Raybould, with whom she was closely allied when the two served in the cabinet together.

Jane Philpott, Trudeau's now-former president of the Treasury board, tweeted a statement announcing her resignation Monday afternoon. In it, she said that, after "serious reflection", she had decided to do the right thing and resign from the government, in keeping with her "ethical responsibilities and constitutional obligations."

Jane Philpott

Philpott went on to explain that the constitutional convention of cabinet solidarity means ministers must defend all cabinet decisions and other ministers publicly, and must speak in support of the government and its policies.

But given the preponderance of evidence supporting Wilson-Raybould's allegations about a concerted campaign of political pressure and veiled threats orchestrated by Trudeau and senior members of his office, Philpott said she could no longer abide by this prinicple.

"Sadly, I have lost confidence in how the government has dealt with this matter and in how it has responded to the issues raised," Philpott said in the statement.

Political analysts in Canada have argued that presenting a united front about Trudeau's innocence would be critical if the Liberals hoped to retain control of government during October's general election.

Philpott is following Wilson-Raybould in resigning from Trudeau's government. Wilson-Raybould resigned in February after being abruptly moved to lead the veteran's affairs department during a cabinet shuffle - a move that was widely regarded as a demotion. Wilson-Raybould claimed that this move was retribution for her refusal to offer Quebec-based engineering firm SNC-Lavalin a deferred prosecution agreement, something she said at least 11 members of Trudeau's government had pressured her to do. She also claimed the prime minister himself insinuated that he wanted her to stymie the government's prosecution of SNC-Lavalin, in the hopes of preventing job losses in his district.

Trudeau claimed that he told Wilson-Raybould that SNC-Lavalin's fate was entirely up to her discretion. Philpott's resignation comes as Trudeau's political opponents are requesting an official inquiry into the scandal.

Read Philpott's full letter below: