"I will be sitting in this seat by 2027," the Prime Minister stated, noting that if the discussion was successful, he might welcome the interviewer into his official residence for another conversation next year.
For a PM, there's never any break for leaders. In the hour before we sat down, Starmer had been speaking with Ukraine's Volodymyr Zelensky and working to work out exactly what had transpired in Venezuela, where his big political chum, US President Donald Trump, had just attacked and captured its leader, Nicolás Maduro.
Once the discussion, which was far more extended than usual, had concluded, Maduro had been charged in New York.
With the year commences, Sir Keir appears to have had something of a refresh. Perhaps even just a bit of relaxation with his family at Chequers, the prime minister's rural getaway.
This appeared to have put him in a more positive mood than at the difficult conclusion of 2025, a awful political year for him.
Yet, are he and his allies kidding themselves if they reckon his fortunes are set to improve?
The grisly reality for the PM is that many of his fellow MPs believe he's underperforming at his job. A faction of them would sooner gamble and get him out in 2026.
However Sir Keir was rejecting the idea when we spoke on Saturday morning.
On several occasions he stated he'd be "judged at the general election", insisting no one would remove his term from him – despite the fact that the best chance of halting Nigel Farage and Reform UK reaching No 10 might be for Labour to replace its leader.
"We are in the fight of our generation and I intend to be at the forefront," he said.
The issue for the prime minister is that he will be scrutinised long before then – in a major set of elections in May throughout the UK. He attempted to protest, maybe too much, that they are about who runs local authorities, and who runs the governments in Holyrood or Cardiff – and not about Westminster.
True – in part. But even though he may be reluctant to concede it, No 10 will be held accountable by those elections too.
Despite this, Sir Keir stating that there were no circumstances under which he would step down, should a his colleagues contested his leadership for the job, if those elections be disastrous for Labour.
He tried to account for his low poll ratings by saying the electorate was understandably eager for things to improve. He aimed to persuade me, and the nation, that this year would be different.
The economy would recover despite rising unemployment, he claimed, when strategies the government put in place during their first turbulent year began to show results.
His core point is that in 2026 the country will "see an improvement".
The prime minister may have spoken with greater vigour than observed from him for a some time – calmer, perhaps, with a longer slot to talk.
But despite facing demands from various quarters for a more decisive strategy, with much more political vision, more urgency, more pace and more immediacy, his points were repeated ones.
Given that he is in such significant political peril, is a different approach required a new narrative?
No administration, and especially not one that has been struggling in the polls for an extended period, has everything its as desired.
Sir Keir's challenges are not just because governing is hard, but because he and his colleagues have faltered, even in the recent past.
The prime minister expressed regret that he regretted saying he was "pleased" to welcome back the Egyptian-British activist Alaa Abd El Fattah to the UK following an controversy when comments he'd previously made – such as calls for Zionists and police to be killed – resurfaced.
Starmer attributed it to "the process" for not realising what the activist had said before – a fancier way of saying not my fault.
And he is inviting evident political perils as the year unfolds. His friendship with the US president entails a new risk after Trump's intervention on Venezuela.
Based on years of interviewing Sir Keir Starmer, a ex- human rights lawyer who was against the war in Iraq, over a long period, the notion he would be at ease with these events seems far-fetched.
He told me he was a "longtime champion of international law" but we "simply lack the full picture at the moment".
Opponents wanted him to criticise the action prior to the interview. And the administration is expected to face more pressure to give an definitive view in Parliament in the near future.
There has also consistently been bubbling desire in the Labour party to revisit some of the consequences of Brexit.
Sir Keir disputes he's pursuing that, but his new firmer pledge to integrate further with the European trading bloc – the giant economic European market – will likely trigger protests that he is going back on his vow never to try to undo the decisions that flowed from Brexit.
A decision to align with more of the single market will satisfy many on his side of the party, but it is simple material for Reform and the Conservatives to