“Each of them wins a round and the other won comes back and is more spiteful or more difficult or says more things.
“They have one thing in common and that is neither of them likes to lose out.
“So they carry on batching away.”
The royal biographer continued: “I imagine that the lawyers are working out if there is a sentence or a verb or something that Piers said that they could jump on.
“So I think it is a bit precipitous actually to say she hasn’t come back yet.
“She is a very determined woman, heavily pregnant or not.
“She will want to fight back.”
On his departure from ITV, Piers said: “I had a good chat with ITV and we agreed to disagree.”
He added: “I believe in freedom of speech, I believe in the right to be allowed to have an opinion.If people want to believe Meghan Markle, that’s entirely their right.
“I don’t believe almost anything that comes out of her mouth and I think the damage she’s done to the British monarchy and to the Queen at a time when Prince Philip is lying in hospital is enormous and frankly contemptible.
“If I have to fall on my sword for expressing an honestly held opinion about Meghan Markle and that diatribe of bilge that she came out with in that interview, so be it.”