GB News is now scrambling to dampen speculation over an exodus of staff, including those in senior positions who were supporters of Mr Neil.
His exit followed reports that three producers had left the station last week, amid discontent over the litany of technical problems that have plagued GB News since its launch.
The Telegraph revealed at the beginning of September that Mr Neil was expected to quit GB News after relations with the board and chief executive Angelos Frangopoulos broke down because of disagreements about the direction of the company.
The ex Sunday Times editor took a break from GB News just two weeks after its launch in June, a total of nine shows, saying he needed to “recharge my batteries” and would be back before the end of summer. He has been living at home in France since then.
Mr Brazier has been presenting the show during Mr Neil’s absence, fronting it 41 times.
Mr Frangopoulos is now expected to shore up dwindling viewing figures by reshaping GB News along the lines of opinionated US television channels such as Fox.
The average audience for GB News reached 14,657 last week, well below BBC News at 79,200, according to analysis by TV ratings compiler BARB.
However, Nigel Farage’s evening show remains a bright spot for the channel. Ratings reached as high as 136,000 last Thursday, before drifting down 20,800 the day after.
After much legal wrangling, insiders said lawyers from GB News and Mr Neil had reached an agreement that allowed him to resign as chairman and presenter if he remained a guest commentator across its programmes.
Shortly after the announcement of his resignation, he appeared as a pundit to discuss China’s influence over British universities.
Mr Neil now has free rein to appear as a commentator on rival broadcasters and is already booked to appear as a panellist on BBC One’s Question Time on Thursday night.
In an email announcing the departure to staff, Mr Frangopoulos said Mr Neil had signed a multi-year contract and the company hoped he would stay longer.
“Andrew helped set our tone, our purpose, even our launch date,” he added. “He has been integral to every major programming and hiring decision.”