“Two days later, you told me you wanted me to take a break for the summer,” he continued.
“You did not say you were briefing papers and issuing a statement that accused me of breaching your editorial standards.
“I asked you to change that on the night – pointing out it was defamatory,” the journalist continued. “You ignored my texts and refused to take my calls.
“I now see that you’ve hired Nigel Farage who immediately declared in public that he will not be taking the knee.”
The presenter wrote in the letter that he sees “no option now but to resign”.
GB News kicks off with The Great British Breakfast daily at 6am.