Conference speech day is always a big day for a prime minister, and perhaps no bigger than when it is your first one in the role.

The pitch from Andy Burnham is that “hope comes from honesty,” there needs to be “less drift and more direction” and there needs to be a willingness to say “the things politicians usually avoid.”

On Sunday, he told the BBC he wants to shake up social care in England, but would only be able to do so after a general election given he was committed to the tax promises Sir Keir Starmer made at the last general election.

This prompted a flurry of chat about how his social care plan could be paid for – and in particular the future of what is known as the triple lock, the promise to increase the state pension in line with wages, prices or 2.5%, whichever is the highest.

This was a policy introduced in 2010 by the Conservative-Liberal Democrat coalition government to try to address pensioner poverty.

But plenty of politicians, in multiple parties, have long privately fretted that its cost is ballooning and will continue to do so, but would bemoan how politically difficult it would be to drop it.

It’s a tricky one for the prime minister: he has the leader of the Unite union, Sharon Graham, saying it could be “electoral suicide” to ditch the triple lock.

Meanwhile the markets – which determine the cost of borrowing for the government – are keeping a keen eye on whether Burnham’s promises appear to be financially credible.

In other words, he has to be able to point to things where money won’t be spent, as well as where it will be.

No10 are being pretty coy about precisely what Andy Burnham will or won’t say on all this later on.

They really don’t want to overcook it or overdo it, instead suggesting it is others who have been getting carried away.

But ministers are well aware that a hare is running about it all – and given that, it would be extraordinary if there was no mention of it all, given that promise about “honesty,” candour and trade offs.

Sufficiently extraordinary that his critics would pounce on what they’d see as a precise lack of the very thing he is promising – candour.

Folk I am hearing from this morning suggest, as one figure put it, “people will be surprised on the upside” about how much Burnham will be willing to lean into the options that could be explored as part of Labour’s offer at the next general election.

He will be explicit it will be retained, as promised, until the election.

Instead, it would appear Burnham will seek to seed a conversation about all of the above, without nailing down the details.

His allies see this as a different approach to politics – being open about options, starting a debate but not crudely or abruptly shifting policy.

There is an implicit comparison with Sir Keir Starmer’s ditching of the Winter Fuel Payment – which appeared to come from nowhere and had a near immediate impact.

But that didn’t stop Graham likening the two approaches – claiming “the danger of doing it” is that Labour could “waste” a second hearing which it now has under Andy Burnham.

And so the debate begins.

In the round, though, ministers I speak to are relishing what they see as a return to big arguments, about generational issues with a prime minister willing to wrestle with them in public.

This afternoon we will get a fuller sense of the scope and scale of that – on social care, pensions and much else.

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