In a statement posted on Twitter, Neil said he left the BBC with “no animosity or desire to settle scores”.
Rupert Murdoch, who appointed Mr Neil as editor of The Sunday Times in 1983, is also reported to be planning the launch of a TV station.
The 71-year-old’s stint on the broadcaster’s Westminster programming — most recently presenting Politics Live and the Andrew Neil Show — saw him become a household name for his forensic interview style.
However Mr Neil has announced he will be leaving the broadcaster to launch GB News – a 24 hour news channel that seeks to rival Sky and the BBC with coverage aimed at those who feel “underserved and unheard by their media”, to launch early next year.