Through the fog of war between the political parties at their annual conferences, the contours of the next general election start to emerge.

Election Plan A for the Conservatives in 2015 was to seek a reward for steering the ship through the economic storm – and offering a sprinkling of tax cuts, either just before the election or in the Tory manifesto. George Osborne would deny it, but Labour suspects his quick, deep cuts, while designed to satisfy the financial markets, had a secondary purpose: to align the political and economic cycles.

Now, however, ministers acknowledge the global economic storm is so strong that the damage will almost certainly still be evident in 2015. The sunlit uplands may not be reached until after the election.

"Never mind the light; we might still be in the tunnel," one senior Tory moaned. On the face of it, this looks like bad news for the Tories. And yet wise Labour heads know that, unless their party regains its reputation for economic competence, voters may decide in uncertain times to hold on to nurse for fear of something worse. It happened at the 1992 election.

So in 2015 the Tories will need another story and this week it became clear at their Manchester conference what it will be: a choice between David Cameron and Ed Miliband. The Tory slogan was "leadership for a better future" and "leadership" was the theme of Mr Cameron's speech. He mentioned the L-word 19 times. Behind the scenes, there was tension over how to marry strong leadership from the top with his flagship Big Society project, based on devolving power to the bottom. "So much of my leadership is about unleashing your leadership," was his clumsy attempt to square the circle.

It was significant that the Big Society got only two mentions. I had expected more, especially after the August riots. Perhaps this was the moment when Mr Osborne, whose relentless focus is on winning a majority in 2015, got the upper hand over Steve Hilton, Mr Cameron's influential adviser and chief architect of the Big Society; his main priority is to force through as much change before 2015 in case the Tories don't retain power. This is the fault line that runs through Team Cameron. The other reason the Tories will go big on leadership is that they smell weakness in Mr Miliband. OK, I know parties always say that about the other lot. But Tory officials testify to me under oath that their focus groups show that people spontaneously describe the Labour leader as "weird".

When YouGov polled 2,300 voters for the ConservativeHome website, 39 per cent described being "Odd Ed" as Mr Miliband's biggest weakness, and only 14 per cent said "Red Ed". True, the two options were put before them so it was something of a leading question. But the Cameroons are excited. "We should say that everything Labour does is a bit weird, because it plays to what people instinctively think of Miliband. It's dynamite," one said.

Conversely, Labour detects weaknesses in Mr Cameron's armoury. The cack-handed advance briefing of his speech, saying he would tell people to pay off their credit and store card bills, exposed the Prime Minister's Achilles heel, Labour strategists say: being out of touch with ordinary people. Back in 2005, when the Cameron-Osborne duopoly took over the party leadership, some Tory greybeards worried about the perception of having "two posh boys" at the top. It is even more dangerous in hard times. Mr Cameron is well aware of this.

"I don't live in some glass bubble," he told Channel 4 News. In his speech, he tried to convince voters – particularly women – that he understands their pain. That is why the discarded section of his draft speech was so damaging.

New polling commissioned by Lord Ashcroft, the former Tory deputy chairman, shows that only 32 per cent of people think that the Conservatives are "on the side of ordinary people, not just the best off", compared to 62 per cent for Labour and 51 per cent for the Liberal Democrats. So Labour, without resorting to class war, will portray Mr Cameron as incapable of living up to his own billing as a "one-nation Conservative" because he is wedded to the closed circles of privilege that deny opportunity to all.

Mr Miliband vowed to smash this system in his conference speech, by far the most significant of the three leaders' addresses this autumn. While Mr Cameron and Nick Clegg essentially gave us a holding operation, Mr Miliband set Labour's bar high; now he has to clear it.

He will hope that the pretty impressive, energetic new Shadow Cabinet he announced yesterday will take some of the load off his shoulders. But that won't stop the Tories making it a choice of two leaders in 2015.

So the next election starts here: "Posh Dave" versus "Weird Ed". The two men would never admit it, but they have one thing in common: they can change their policies, but they cannot change who they are.