Starmer says he knows what's wrong - but can he fix it?

How could he not have been cheerful?

This was the first Labour leader’s conference speech delivered as prime minister in 15 years - 5,474 days if any disconsolate party activists have been counting.

So it was little wonder that Sir Keir Starmer was so rapturously received in by the rank and file in the hall.

The long wait is over. A party leader not castigating the government from the sidelines but describing what the government - a Labour government - will actually do.

Well, up to a point. This was a speech relatively light on new policy and heavy on political framing.

As advertised, the prime minister picked up where Rachel Reeves, the chancellor, left off yesterday - not merely warning gloomily of the tough decisions to come but trying to project more optimism about the dividends which will come from making the tough choices.

Again, though - only up to a point. No more “false hope”, Starmer said. No more “easy answers”.

Yes, he said, there would be light at the end of the tunnel. But it is still very clearly the government’s view that there is going to be a long tunnel.

Perhaps the most consistent, and fresh, theme was that of trade-offs - in areas where the prime minister said his Conservative predecessors had been dishonest.

Cheaper electricity, he said, requires new pylons (that got a notably large round of applause). Public consent for the welfare state requires legislation to stop benefit fraud. Justice requires people living close to new prisons. Tackling illegal immigration requires granting some people asylum.

While insisting there are no easy answers, the selection of trade-offs here did appear to reveal preferences on the prime minister’s part: more pylons, a tougher benefits regime, more prisons, clearer routes for legitimate asylum claims.

Those are clear directions of travel on some thorny policy areas. But more flesh will need to be put on the bones. Take the example of prisons. How precisely will the planning system ensure communities can’t object to or slow down new prisons? How will the new prisons be funded? What kinds of offence does the prime minister believe should and should not result in custodial sentences anyway?

That is the risk - that in the fullness of time this comes to be seen as a speech long on diagnosis but short on prescription.

The inverse is possible too: that this speech sets a framework for the decade of national renewal that Sir Keir continues to describe as his goal.

That requires the government to deliver over the coming weeks, months and years. Can they do so?

That’s a question which is impossible to examine without mentioning the briefings and leakings about Starmer’s Downing Street operation which have been the talk of this conference’s parties and dinners.

The jubilant activists have provided an important morale boost to the top ranks of the Labour Party who - whatever the public denials - are deeply concerned about whether the prime minister has the right team in the right jobs, and deeply divided over the answer.

It may sound mundane given the scale of the challenges Starmer diagnosed in his speech, but delivery in government relies on a Downing Street firing on all cylinders.

Even cabinet ministers have spent much of the past few days privately bemoaning what they see as the deficiencies in how the government is functioning.

The prime minister may need to fix those to fix Britain.