The secretary of state had known a battle was brewing but he had survived similar conflicts with the president before

Rex Tillerson's last significant act as secretary of state was characteristically out of tune with the White House.

Donald Trump's spokeswoman, Sarah Sanders, had avoided any blame of Russia for the poisoning of an ex-spy in Britain, but minutes later Tillerson issued his own statement, which was definitive in supporting the UK assessment that Moscow was behind the attack.

It was the sort of statement of unquestioning support for an ally that would be expected in more normal times, and that was the problem. Trump had said privately but repeatedly that he found Tillerson too ” traditional “.

Most longstanding observers had expected there could be a tweeted reprimand from Trump on Tuesday morning, as there had been several times in the past when Tillerson had strayed from the White House line.

But the dismissal came as a shock nevertheless, at least to state department officials who had accompanied Tillerson on his final foreign tour, to Africa.

The exit was brutal. Trump phoned Tillerson from Us air force One soon after midday, more than three hours after the tweeted proclamation of his firing.

Tillerson managed merely to secure agreement for him to stay on formally until the end of March to oversee a transition.

State department officials had said earlier that he would leave his post immediately and could not confirm whether he would even return to pack up his belongings. A departure date of 31 March was agreed upon, but he relinquished day-to-day running of the department to his deputy, John Sullivan.

When he appeared to build his farewell at the lectern in the state department briefing room, he was clearly depleted and emotional. His voice was on the point of cracking.

[ youtube https :// www.youtube.com/ watch? v= gkoZeiOQd1 8? enablejsapi= 1& rel= 0& showinfo= 0& origin= https :// www.theguardian.com& w= 100& h= 100]

Play Video
1:05

Rex Tillerson: ‘I'll return to private life proud to have served my country'- video

He focused on the selflessness of public service and did not mention the president. He spoke about the values of accountability he had tried to instil in the state department , not the administration's.

Tillerson and Trump's offices even clashed about the circumstances of his deviation. The White House said that he had been given a few days' notice. But a Tillerson spokesman, Steve Goldstein, told reporters it had come as a complete surprise to Tillerson, soon after he landed in Washington at 4am.

Reporters at the state department were told that Goldstein would provide a briefing. Then Goldstein was said to have been” pulled aside into a session “. An hour later the news leaked that he had been summarily fired.

Tillerson had known over the weekend that yet another battle was brewing. He received a call on Friday from John Kelly, the White House chief of staff, according to the Associated Press, but that was apparently to warn him that there might be a tweet” of concern to him” in the pipeline.

But the veteran Texan oilman had survived similar battles before, riding out presidential frustration by marshalling his allies, and affecting a laconic unconcern about the backstabbing ways and means to Washington.

When White House officials unleashed a flurry of unattributable press briefings in late November suggesting that Tillerson was on the way out, he held an early morning meeting with James Mattis- the defence secretary and his close ally- and the two of them ran for lunch with Trump.

After that session, the president disavowed any intention of getting rid of Tillerson, proclaiming it” fake news “.

That incident led to speculation that there was a” suicide pact” among traditional conservatives in the cabinet- including Tillerson, Mattis and possibly the treasury secretary, Stephen Mnuchin- in which they would all threaten to leave if one of them was threatened.

But if the pact ever existed, it failed to save Tillersonthis time- perhaps because he was out of the country and unable to rally resistance. On the last leg of his African tour, he closed himself in his room for a day, claiming sickness, and then announced he would be leaving for home a day earlier than scheduled.

By the time his airliner landed in Washington, it was too late: the execution by tweet followed just a few hours later.

Within minutes, Nikki Haley, the US envoy to the UN- who had pursued her own hawkish foreign policy in New York without reference to Tillerson or the state department- put out her own tweet. Haley described the reshuffle as a” great decision” and said nothing about Tillerson.

Nikki Haley (@ nikkihaley) Congratulations to my friend and soon to be Secretary of State Mike Pompeo! Great decision by the President.

Read more: www.theguardian.com