The country’s ethics commissioner said that Mr Trudeau engaged in “flagrant attempts to influence” the Attorney General, Jody Wilson-Raybould.

Mr Trudeau and his aides are accused of pressuring the Attorney General into abandoning the prosecution of Montreal-based construction giant SNC-Lavalin.

Mario Dion, the independent ethics commissioner, said they had tried to undermined and discredit a decision by federal prosecutors that the firm should be put on trial for corruption.

Senior prosecutors had pursued the company over fraud and bribery stemming from its activity in Libya between 2001 and 2011 but Mr Trudeau lobbied for a deferred prosecution agreement, which did not prevent the firm from bidding on federal contracts.

When Ms Wilson-Raybould refused to overrule prosecutors she was shuffled out of her role.

Mr Dion wrote: “The evidence showed there were many ways in which Mr Trudeau, either directly or through the actions of those under his direction, sought to influence the attorney general.”

“Because SNC-Lavalin overwhelmingly stood to benefit from Ms Wilson-Raybould’s intervention, I have no doubt that the result of Mr Trudeau’s influence would have furthered SNC-Lavalin’s interests. The actions that sought to further these interests were improper,” he stated in his decision.

“The prime minister, directly and through his senior officials, used various means to exert influence over Ms Wilson‑Raybould. The authority of the prime minister and his office was used to circumvent, undermine and ultimately attempt to discredit the decision of the director of public prosecutions as well as the authority of Ms Wilson‑Raybould as the crown’s chief law officer,” he added.