ONE Nation is tonight desperately trying to save face after an embarrassing and very public rejection and the fastest political defection on record.
Pauline Hanson's party is in tatters after One Nation senator-to-be Fraser Anning quit the party only an hour after being sworn in, opting to run as an independent instead.
It was a massive snubbing for Hanson, who sulked in her office as her fellow Queenslander took the oath to serve in the Upper House without her.
His departure caught Senator Hanson by surprise and underlined the instability of One Nation's federal team, despite what the party was saying publicly.
So far One Nation has been home for six senators, with two being disqualified on constitutional grounds and Senator Anning jumping elsewhere. It now numbers just three.
Senator Anning was the replacement for dual citizen Malcolm Roberts who was dumped from the Senate by the High Court.
Last-minute discussions failed to mend his difference with Senator Hanson, which are understood to involve the role in the party of Senator Hanson adviser James Ashby.
Speculation now is whether Senator Anning will join the parties of the two senators who this morning walked in with him.
The first hint of a One Nation split came when instead of being escorted into the chamber by party colleagues, Senator Anning was accompanied by Australian Conservatives leader Cory Bernardi and Liberal Democrat David Leyonhjelm.
Senator Hanson wasn't there and the two other One Nation senators - Brian Burston (NSW) and Peter Georgiou (WA) - watched from their seats.
Senator Leyonhjelm's office said in a statement he had "vouched for new One Nation senator Fraser Anning in the chamber this morning, in the company of Senator Bernardi".
"Senator Leyonhjelm did so with pleasure at the invitation of Senator Anning," said the statement.
The Anning about-turn is a remarkable move given it is hugely unlikely he would have reached the Senate without the Hanson name on the ballot paper at the double dissolution election last year.
And he was elevated by the High Court, accepting advice from the Australian Electoral Commission, because he was next on the One Nation ticket.
It is understood Senator Hanson and Senator Anning only spoke of their differences this morning, with suggestions he had declined to take her calls earlier.
There was an attempt at mediation by the two other One Nation senators, but that failed.
Earlier this month Senator Hanson's chief of staff James Ashby was accused of threatening and attempting to bully a staff member of a crossbench senator's office.
He was angry the anonymous staffer had been talking to then plain Mr Anning, a Queensland publican who gained just 17 votes personally in the 2016 election.
Senator Hanson had withheld her endorsement of Senator Anning to replace Mr Roberts.
An official complaint from the staff member claimed: "Later that week, Mr Ashby contacted my employer by phone and tried to pressure him into terminating my employment."
The complaint is still being considered and Mr Ashby has declined to comment.
The Anning defection forced both camps into uncomfortable statements on Monday. On her Facebook page, Senator Hanson wrote that Senator Anning "has abandoned the party to stand as an independent until something better comes along".