The surest way to look prime ministerial is to be the prime minister. The point is less glib than it perhaps sounds. Conservatives cherish opinion polls showing that David Cameron has a substantial lead over Ed Miliband on measures of personal authority. Voters generally think Cameron is stronger and more charming than his Labour rival. On the specific question of who looks more like a prime minister, one recent survey had the incumbent 40 points ahead.

Well, people would say that, wouldn’t they? It is easier to picture someone working in Downing Street when he already lives there. That is one Labour defence of the leader’s tricky personal polling. Meanwhile, the party regularly has double-digit leads over the Tories.

Most Labour MPs think that the margin is not wide enough. Many worry that it expresses midterm dissatisfaction with the government more than enthusiasm for regime change and that just a smidgen of economic growth could lead to an abrupt reversal. Downing Street is confident that a presidential-style election battle between the two leaders will halt Mili­band’s momentum.

The view that Britain holds presidential elections disguised as parliamentary ones is commonplace in Westminster – and wrong. If it were so, Cameron would have crushed Gordon Brown to seize a majority. He didn’t because enough voters rejected his party, sticking with Labour despite its flawed frontman. It is the media coverage that is presidential but voters see beyond that.

Way of the jargon

It is possible that the people who tell pollsters that they intend to vote for Labour will do exactly that. It also seems unlikely that those who almost backed Cameron as the ambassador for a new kind of Conservative Party but doubted the sincerity of the change will give him the majority in 2015 that they denied him in 2010.

Those conditions have bred a kind of cynical optimism in some Labour quarters. This view has the party sneaking up on power, doing little more than waiting for divisions between the coalition parties and within them to shred the government’s credibility.

Miliband’s strategists reject the idea that goal-hanging is part of the plan. They know that voters punish parties deemed to be hiding their real agenda. By contrast, they assert, Miliband could not be more open about his intentions: he wants to refashion the British economy so it serves the many, not the few.

What worries many shadow cabinet ministers is not the ambition but the lack of supporting policy detail and the impenetrable language in which the vision is expressed. There is unease at the way Miliband surrounds himself with academics and theorists who indulge the leader’s fondness for jargon – advertising “pre-distribution”, for example, as the antidote to inequality – instead of challenging him to speak in plain English. The atmosphere of the faculty seminar in the leader’s office hinders what one aide describes as “Project ‘Ed’s Charisma’” – the mission to help Miliband loosen up and make it easier for people to imagine him as prime minister.

Partly with that end in mind, Miliband will start this year’s annual conference in Manchester with a question-and-answer session on 29 September, open to all comers at a venue outside the police security cordon. It is an innovation not without risk, aides concede. The crowd won’t be vetted to weed out hecklers. Yet the leader’s minders say that he performs better as “the real Ed”, engaging with the public, unimpeded by lecterns and released from the conventions of political rhetoric.

This year’s keynote address will, I am told, build on last year’s disquisition on “responsible capitalism” but with lessons learned from the hostile reception that lecture initially received. The Miliband camp is certain that the underlying thesis – distinguishing between “productive” and “predatory” commerce – was the right one. It belatedly won plaudits, including from some conservative commentators, as a more interesting analysis of the challenges facing the country than was offered by the Lib Dems or Tories. The message, however, lost coherence amid endless revision. It suffered from being written by committee, as even members of the committee admit.

This year, Miliband has spent more time working on the speech at home. He is said to be determined that it is his personal vision, delivered in his own words (a prospect that provokes cold sweats among those Labour sceptics who long for more campaign-ready sound bites). The emphasis will be on the kind of society that Miliband wants to see emerge from the ashes of austerity. It is a message designed in part to expose Cameron’s failure to offer an optimistic account of why he wants to govern. Even many Conservatives worry that their leader comes across as little more than a posh dilettante overseeing a bodge job on the public finances.

Emperor’s new clothes

No 10 is alert to Cameron’s crumbling image. Focus groups are sounding resentful. Views that the Prime Minister “doesn’t understand people like me” are, according to a senior Tory source, hardening into a feeling that he “doesn’t like people like me”.

Yet there doesn’t appear to be much concern in Downing Street that Miliband’s status will rise as Cameron’s popularity falls. Nor is there willingness to engage with the argument that the Labour leader is making about the economy and society. His account of systemic flaws in British capitalism is dismissed as the sophomoric ramblings of a political lightweight, taken seriously only by people who are comforted by the sound of soft left erudition and afraid to confront the possibility that there might be no substance behind it. “It’s a case of the geek emperor’s new clothes,” says one No 10 insider.

Miliband is relaxed about that scorn. He believes that the Tory leadership is too ideologically blinkered or too arrogant to heed the desire in Britain for a dramatic change in political direction. Even if he is right about that, he has a long way to go before he persuades people that the change voters want is to a Labour government, with him as prime minister. Still, the task is made easier as long as the incumbent seems to think the best qualification for doing the job is simply looking the part.