"I'll remain in the same position by 2027," the Prime Minister remarked, joking that if the discussion was successful, he might invite us into Number 10 for a follow-up chat next year.
There is never any break for prime ministers. Shortly before our chat started, Sir Keir had been in calls with Ukraine's Volodymyr Zelensky and working to decipher exactly what had occurred in Venezuela, where his close ally, US President Donald Trump, had just attacked and captured its leader, Nicolás Maduro.
Once our lengthy talk, which was far more extended than normal, had ended, Maduro had been charged in New York.
As the year starts, the Prime Minister seems to have had a kind of a reboot. Maybe even just a bit of relaxation with the family at Chequers, the prime minister's country retreat.
This appeared to have left him in improved morale than at the saggy end of 2025, a dreadful year politically for him.
But are he and his supporters being unrealistic if they believe his standing are about to improve?
The grisly truth for the PM is that many of his fellow MPs are convinced he's not very good at his job. Some of them would rather gamble and remove him in 2026.
However Sir Keir was dismissing such talk during our conversation on Saturday morning.
Multiple times he stated he'd be "evaluated at the poll", maintaining nobody would remove his term from him – even if the most effective strategy of halting Nigel Farage and Reform UK entering No 10 might be for Labour to change leader.
"We are in the fight of our generation and I plan to guide the party," he affirmed.
The problem for the prime minister is that he will be scrutinised well ahead of then – in a mega set of elections in May throughout the UK. He tried to contend, perhaps excessively, that they are about who runs councils, and who runs the devolved administrations in Holyrood or Cardiff – and not about Westminster.
True – up to a point. But although he may be reluctant to concede it, No 10 will be held accountable by those elections too.
Despite this, Sir Keir implying that there were no circumstances under which he would resign, should a his MPs ran against him for the job, if those elections be very poor for Labour.
He sought to rationalise his low poll ratings by saying the voters was understandably impatient for things to improve. He tried to convince the interviewer, and the public, that 2026 would be distinct.
The economic situation would recover notwithstanding rising unemployment, he claimed, when plans the government put in place during their first turbulent year began to show results.
His central argument is that this year the country will "see an improvement".
The PM may have communicated with renewed vitality than I've seen from him for a some time – calmer, maybe, with a longer slot to talk.
But despite facing calls from various quarters for a more decisive approach, with increased political vision, more urgency, more speed and more urgency, his points were repeated ones.
When he finds himself in this much political difficulty, should he consider a new narrative?
No government, and especially not one that has been struggling in the polls for many months, gets everything its own way.
The Prime Minister's problems are not only because governing is challenging, but because he and his colleagues have made mistakes, even in the recent past.
The PM told me that he was sorry for saying he was "happy" to see the return of the Egyptian-British activist Alaa Abd El Fattah to the UK after an outcry when comments he'd made in the past – including calls for Zionists and police to be killed – resurfaced.
Starmer blamed "the process" for not realising what the activist had said before – a more diplomatic way of saying not my fault.
And he is inviting obvious political risks as the year progresses. His close relationship with the US president entails a new jeopardy after Trump's strikes on Venezuela.
Having interviewed Sir Keir Starmer, a former human rights lawyer who opposed the war in Iraq, over a long period, the thought he would be at ease with these events seems unlikely.
He stated he was a "longtime advocate of international law" but the public "just lack the entire story at the moment".
Opponents wanted him to criticise the action before the interview. And the administration is likely to face more pressure to give an clear view in Parliament in the near future.
There has also consistently been simmering tension in the Labour party to revisit some of the results of Brexit.
Sir Keir disputes he's pursuing that, but his new firmer commitment to move closer with the EU's single market – the vast economic European market – will likely provoke howls that he is reneging on his vow never to try to reverse the choices that stemmed from Brexit.
A move to cosy up to more of the single market will satisfy a faction on his side of the party, but it is simple material for Reform and the Conservatives to
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