Theresa May is held in far higher regard by voters as a leader and a person than Boris Johnson, according to a detailed analysis conducted after the party conference season.

Not only do voters from all parties, including the Conservatives, clearly prefer May to Johnson as a Tory leader, but they also see the prime minister as more decent, decisive and trustworthy than the former foreign secretary.

The findings are revealed today in a survey by Opinium for the Observer that was taken after the party conference season, during which Johnson repeatedly attacked May’s Chequers plan for Brexit as a betrayal of the people.

Strikingly, May’s lead over Johnson on questions of leadership and character is even higher among Conservative supporters than the electorate at large.

Last Tuesday at the Tory conference in Birmingham Johnson stepped up what Tory MPs believe is now a fully-fledged campaign to replace May by criticising not only her approach to Brexit but also what he said was a lack of ambition in the government’s domestic agenda.

“If I have a function here today it is to try, with all humility, to put some lead in the collective pencil, to stop what seems to me to be a ridiculous seeping away of our self-belief, and to invite you to feel realistic and justified confidence in what we can do,” he told a packed hall of Tory delegates. But in a poll conducted mainly after May’s concluding speech to the conference on Wednesday, it is May who seems to be trusted more to run her party and the country, and is seen as a more likable person.

Among voters at large, almost twice as many (32%) think May is the best person to run the Conservative party compared with Johnson, who is preferred by 17%.

Among Tory voters, the gap between the two is far more clearly in May’s favour, with 62% thinking she is best to lead the party, compared with 15% who believe Johnson would be better.

When asked about their individual qualities, voters prefer May to Johnson on almost all counts, with Conservative voters again backing her by higher margins than supporters of all parties.

While 47% of all voters think May is “a decent person”, only 30% have that view of Johnson. Among Tory supporters, May is seen as decent by 83% against 48% for Johnson.

Some 43% of all voters see May as having “the nation’s best interests at heart” against 30% who think Johnson does. Among Tory supporters, 81% say May has the nation’s interests at heart against 52% who think Johnson does.

Asked who is a strong leader, 32% of all voters say May, against 27% for Johnson. Among Tory supporters May is further ahead again, with 63% believing she is strong against 39% who say Johnson is.

Only 23% of all voters think May is “vain”, against 55% who think Johnson is. Among Conservative backers just 13% think May is vain, while 55% think Johnson is.

When asked whether May and Johnson are “divisive”, 37% of all voters say May is, against 50% who say Johnson is. Among Tory supporters 43% think May is divisive while 56% say Johnson is.

Facebook Twitter Pinterest Tins of candles on sale at the Tory conference venue in Birmingham. The party failed to light up the public, however, with its overall support remaining unchanged. Photograph: Stefan Rousseau/PA

Overall, the Conservatives and Labour emerge neck and neck in terms of public support at the end of the conference season, with both on 39%. The Tories are unchanged compared with a week ago while Labour has risen three points, having dropped to 36% immediately after its own conference in Liverpool, which closed on 26 September.

By a narrow majority, people think the Conservatives performed best during the conference season. Some 28% think the Conservatives performed the best compared with 24% who believe Labour did. Some 32% think the Conservatives would tackle the challenges of the future best, against 25% who believe Labour would.

In numbers

83%

of Tories see Theresa May as a decent person against 48% for Boris Johnson; it is 47% and 30% among voters of all parties, including Tories.

81%

of Tories say May has nation’s best interests at heart; 52% say Johnson. It is 43% and 30% among all voters.

63%

of Tories see May as a strong leader against 39% for Johnson. Among all voters it is 32% and 27%