The security reshuffle saw senior military and intelligence officials reinstated to the NCS after they had been bumped at the time of Bannon's appointment in the early days of the administration. It was read through two prisms - new Trump National Security Adviser, US Army Lieutenant General HR McMaster is asserting himself; and after 75 days of administration chaos, when push comes to shove, Trump can be convinced to reshuffle even his closest aides.

McMaster has been settling in since he replaced his predecessor, the former US Army General Mike Flynn, who was sacked in February, after he was revealed to have lied about his communications with Russian ambassador Sergey Kislyak during the presidential transition.

Last month McMaster was depicted as something of a eunuch, when Bannon and Trump son-in-law and counsellor Jared Kushner intervened to thwart his sacking of NSC intelligence director Ezra Cohen-Watnick. The Flynn appointee was outed last week as the source of leaked intelligence documents linked to congressional investigations of Trump's Russia connections.

But fast-forward to Wednesday and McMaster seemingly has total control of his sphere - and Bannon, who has no security experience, has been banished from his front-row seat in a body that is critical in setting national security policy.

The problem with Bannon, as McMaster reportedly told Trump and others in the White House, was that his presence politicised the NSC, a complaint registered vocally by Republicans and Democrats alike at the time of Bannon's NSC appointment.

Bannon, former chairman of the right-wing Breitbart News, parsed his removal as indicative of a job done - a makeover of the NSC from how it had operated under the previous administration. Others in the White House insisted that it did not amount to a demotion, claiming that Bannon had rarely attended NSC meetings; and neither did it represent a loss of confidence in Bannon by the President.

Another spin line from the White House was that Bannon's key NSC duty had been to keep an eye on the disgraced Flynn whose management style was described as "combative".

Bannon's appointment, the insiders said, had always been a temporary, transitional posting, though that was not stated in the face of so much criticism at the time and when McMaster took over, Bannon and some of his loyalists insisted that his NSC post would not change.

Similarly, that spin did not address reports at the time of Bannon's elevation that Trump had been irked, apparently because he had signed, but had not read the order authorising Bannon's appointment to the NSC.

In a comment that few understood, Bannon said of this first stumble in his unstoppable rise: "[Obama National Security Adviser] Susan Rice operationalised the NSC during the last administration. I was put on to ensure that it was de-operationalised."

Bannon's security downgrade was read as McMaster putting his own stamp on the security apparatus, in a way that cements his control of advice to a divided White House. As McMaster has kept a low profile, he reportedly has become a significant conduit for foreign diplomats and has quickly earned the confidence of some in Trump's inner circle.

Some detected the hand of Kushner, who has become critical of Bannon, which could point to a significant shift in White House power relationships, with Trump edging away from Bannon's ideologically driven team.

The move represents a return to the traditional NCS format of meetings attended by Cabinet members, senior intelligence officials and the chairman of the Joint Chiefs of Staff - but with an ascendant McMaster more firmly in charge.

John Bellinger, who served as a legal adviser to the NSC in the second Bush administration, told The Washington Post: "If the thrust of all of these changes is that Steve Bannon has been removed from the NSC and the principals committee...that may show you that the White House is heading in a slightly different direction in terms of decision-making".

Eric Edelman, a defence policy official under George W Bush, told Politico magazine: "I get a sense that people are going, 'Ding-dong, the witch is dead'. The only thing he doesn't appear to have is a seat at the NSC principals committee, and it's not clear how important that will be".

Describing Bannon's NSC banishment as "a good move", Senator John McCain, a big GOP voice on security and defence matters, said: "I said at the time that I didn't think a political adviser should be a member of that body because it's never been, so I think it's the right thing to do".

Republican Congresswoman Ileana Ros-Lehtinen, a former chair of the House Foreign Affairs Committee, tweeted: "Steve Bannon's removal from National Security Council is welcome news".

But Flynn's son, Michael G Flynn, who was sacked from Trump's transition team, was enraged, tweeting: "Flynn/Bannon most loyal to [Trump] (both out at NSC)???McMaster wont say 'Radical Islam.' Is [White House] serious abt defeating our enemy?"