The YouGov poll of Conservative Party members for the channel found 66% in favor of Foreign Secretary Truss, while 34% support former Finance Minister Rishi Sunak.
The breakdown includes only those who have voted or plan to do so.
With the Tories currently holding a majority in Britain’s Parliament, either Truss or Sunak will become the country’s prime minister when current leader Boris Johnson steps down early next month.
The poll found that more than half (57%) had already voted before the September 2 ballot deadline.
Just over a quarter of those who have yet to vote said they have not yet decided who to support.
The poll showed Sunak’s support had risen 2% since a similar poll two weeks ago, but “the incremental improvement…wouldn’t be enough to save him the competition,” Sky News said.
The two leadership contenders have fought a fierce battle in recent weeks, marked by frequent hostile briefings and counter-briefings from their camps.
The opinion poll highlighted the Conservative base’s chasm with the Parliament Party and found Johnson would still win if he contested the leadership race, with 46% saying they would vote for him.
He announced he would step down as leader of the ruling party earlier this summer, following mass resignations among members of his cabinet and MPs who grew frustrated with his scandal-hit leadership.
The YouGov poll was conducted among 1,089 of the Conservative Party’s roughly 200,000 members.
The winner will be announced on September 5 and the winner will take over the following day.
Candidates will stage the next of a dozen hustings at the summer competition in the northern English city of Manchester on Friday evening.
- Editor / additional report by AFP