Ed Fast, a former trade minister under Stephen Harper, has turned down an offer to serve in Andrew Scheer's "shadow cabinet," citing concerns about his leadership.

In an interview with CBC News, Fast said he spoke with the Conservative leader this week about where he might fit into the lineup of critics tasked with scrutinizing Liberal cabinet ministers.

"I expressed my desire not to be included at this time," he said.

"Mr. Scheer, I believe, is entitled to surround himself with a team that fully supports his leadership and I'm looking forward to remaining fully in the affairs of our Conservative caucus and to holding Justin Trudeau to account for his actions, his words and how he leads this country."

Fast declined to provide details of his private discussion with Scheer, or say what role he was offered. In the last Parliament, he served as the party's environment and climate change critic.

Scheer's spokesman Simon Jefferies said that the shadow cabinet, which is "50 MPs strong," is ready to hold Trudeau to account.



"Mr. Scheer appreciates the efforts Ed Fast put into developing the Conservative environment plan as the previous shadow minister and Ms. Kerry-Lynne Findlay will continue to build on his work as the new shadow minister for the environment and climate change," he said in an email.



"Mr. Fast will continue to serve the Conservative caucus in different ways."

Rachael Harder, the party's status of women critic in the last Parliament, is also no longer part of the Conservative shadow cabinet. Both Harder and Fast endorsed Erin O'Toole in the last Conservative leadership contest.

Fast's decision delivered another public blow to Scheer's leadership. He's facing mounting criticism over his election performance and Conservative MPs and grassroots party members are debating whether he should stay on as leader through the next election.

Several failed candidates and party operatives have publicly questioned his leadership and suggested he should step aside before a leadership review at the party convention in April.

Scheer vows to fight for job

On Thursday, Scheer made it clear he intends to fight to keep his job.

"I am staying on to fight the fight that Canadians elected us to do. Now is not the time for internal divisions or internal party politics. That is an unfortunate part of the Conservative tradition in this country, but it's essential that we stay focused on the task at hand," he said.

"I will be making the case to our members that we need to stay united and focused, and will be seeking a mandate to do that in April."

Conservatives gather in Toronto for the biennial convention in April.

Former cabinet minister John Baird is conducting an external review of the party's election results, to help Conservatives understand the reasons for the party's defeat.

As part of that review, Baird is conducting interviews with candidates and campaign staff. Fast said he has provided input to that process.

"I have shared with John Baird my concerns about how the last election was run," he said. "John has met with many other stakeholders as well, and I'm going to await the outcome of that process, and I think the party will be in the position to respond at that time."

Some MPs will keep the files they held before the election. James Bezan, for example, remains defence critic, Pierre Poilievre is still the finance critic, O'Toole stays on as foreign affairs critic and Marilyn Gladu continues as the health critic.

Others have been tasked with new files, including Michelle Rempel Garner — now the critic for industry and economic development — and Peter Kent, now critic for immigration, refugees and citizenship.

Here is the full list of critics: