Lord Frost has said the Conservatives can still win the next general election if they focus on winning back Leave voters who have deserted the party.
The Tory peer warned that focusing on Remainers is “surely a losing strategy”.
He instead urged Rishi Sunak to target 2019 Red Wall voters who swung from Labour to Boris Johnson but have since lost faith in the party.
Writing in The Telegraph, Lord Frost said: “So winning back our 2019 voters makes the difference between victory and defeat.
“Get those 2019 voters back, recreate that coalition – now disintegrating but still plausibly in being just a year ago, well beyond the departure of its supposed catalyst in Jeremy Corbyn – and we can still win.
“Trying to win back Remain voters when we remain so unpopular among them is surely a losing strategy.”
Lord Frost called for the Prime Minister to emulate Mr Johnson’s “relentless optimism” that leaving the EU could “make life better for those who had entrusted the Tories with their vote and for those who yet might”.
He warned against giving the “impression that we see Brexit as an awkward and embarrassing legacy” as “all we are doing is signalling we don’t seem to believe in our central policy”.
He said: “Why, then, should anyone else? That makes it all too easy for Starmer to do what he really wants to do: take us back into the single market and customs union, as a first step.”
Lord Frost said 2019 voters in the northern Red Wall seats, formerly Labour’s heartlands, wanted the “restoration of national independence to make a difference to their lives”.
But he said they are abandoning the Tories because they “see us chasing after those who did well out of the old order and don’t want to change it”.
It comes after Lord Frost last month launched his bid to become a Tory MP at the next election.
The former Brexit minister confirmed that his name has been placed on a Conservative candidate list.
Lord Frost said: “I am grateful to the party authorities for accepting my application as a potential Conservative candidate for the House of Commons, the centre of our national political life.
“I have not yet applied for any seat and am considering my next steps. Meanwhile I look forward to campaigning for the party and for Conservative principles in the months to come.”
Lord Frost, who is popular on the right of the party, has previously floated the idea that he could run to become an MP despite his peerage.
If he gains a seat in the Commons, he would have to give up his position in the Lords.