Former Brexit minister Lord Frost also said pushing ahead with the National Insurance rise was “not Conservative” and would weaken growth. But he called on the party’s warring factions to call a truce following the bruising confidence vote.
“Both sides need to respect the result,” the Tory peer said.
“The Prime Minister’s opponents have got to accept the fact that he won.
And his supporters and the Prime Minister himself have got to accept that a change of policy is needed - that when nearly 150 of your own MPs vote against you that is a sign of a big problem and the problem is that we are delivering an economic policy that is not going to deliver prosperity and wealth.
“If we can change that, if he can change that, then he can get on to a different path and save the premiership and the Government.”
Lord Frost insisted Mr Johnson is “always best when he trusts his instincts and does unconventional things” and urged him to be “much more radical” in his approach to the nation’s finances.
The senior Tory said “virtually no economy” had cured a deficit problem by cutting spending and raising taxes, adding: “We need to improve productivity and investment, not weaken it.”
Lord Frost went on to call for the whole party to back legislation to ease tensions caused by the Northern Ireland Brexit protocol, which could be introduced in Parliament as early as today.
He negotiated the original settlement with Brussels.