The senior MP, who chairs parliament's defence select committee but was stripped of the Tory whip in July, said the party should stick to its sensible and fiscally responsible roots.
He said that "haemorrhaging the one-nation voice" would lead to electoral disaster and called on the under-fire prime minister to "regroup very, very quickly" by bringing in the "full complement of talent".
As Truss prepares to give the closing speech at a Conservative party conference that has been plagued by divisions and several U-turns, she was urged by Ellwood to show humility and acknowledge that "some serious mistakes were made".
"She needs to be more inclusive, more open and transparent in where she wants to take Britain - reconfirming fiscal responsibility as the hallmark of where our party sits," he said.
Despite having not held the Tory whip for three months, due to not supporting Boris Johnson in a no-confidence vote because he was in Moldova, Ellwood said he absolutely still felt at home in the Conservative party. "If people like myself and those who are like-minded think about departing the party, where does that leave the party?" he said.
"It's the amalgamation of all the voices in the party that usually provides that moderate centre-right, sensible, fiscally responsible leadership that the nation then supports and elects.
"As soon as you start haemorrhaging the one nation voice of the party, we will not have that mass appeal. We will not be able to win elections because we will fail to secure support from the centre ground."
Ellwood said talk of immediately toppling Truss was premature, and she still had a chance to salvage her premiership by ensuring the chancellor's medium-term growth plan, pencilled in for 23 November, and Office for Budget Responsibility forecasts were brought forward.
This story is from the October 06, 2022 edition of The Guardian.
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This story is from the October 06, 2022 edition of The Guardian.
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