Nearly 60% of Conservative supporters do not believe Boris Johnson has what it takes to make a good prime minister, according to a new poll.
The number of Tory backers saying the former foreign secretary lacks the qualities needed by an occupant of Number 10 has risen seven points to 58% since September, the Ipsos MORI survey states.
Conservative supporters believing Johnson has the right prime ministerial abilities dropped from 39% to 32% in the same period.
Other potential Tory leadership contenders receive similar approval ratings, with 32% of Conservative backers saying foreign secretary Jeremy Hunt and home secretary Sajid Javid have what it takes to be PM.
While work and pensions secretary Amber Rudd is just behind on 31%.
But the possible leadership rivals score smaller negative ratings than the ex-foreign secretary.
Javid is seen as lacking what it takes to be prime minister by 40% of Tory supporters, while 38% take the same view of Rudd, and Hunt gets a 36% score.
Environment secretary Michael Gove is seen as good prime minister material by 30% of Tory backers, with 45% disagreeing.
While ex-Brexit secretary Dominic Raab is rated as having what it takes by 20%, with 44% taking the opposite view.
Three in five Conservative supporters, 60%, agree that Theresa May has the qualities needed to be a good prime minister, while 30% disagree.
Among all voters, the figures are almost reversed, with 30% saying May has the qualities needed by a good PM, and 57% taking the opposite view.
The situation is worse for Labour leader Jeremy Corbyn, with 21% of all voters saying he has what it takes to be in Downing Street, while 67% disagree.
Views are split on when May should stand down as prime minister, with 36% of all voters saying the Tories should change their leader as soon as possible, a rise of seven points since September.
While 30% of voters think the Tories should elect a new leader once Britain has left the EU but before the next general election.
And 24% believe the Conservatives should get a new leader after the next general election.
Of Conservative backers, 17% think the party leader should be changed as soon as possible, with 39% saying it should happen after Brexit but before the next general election.