The barrister added: “Dr Evans had said to the jury that Lucy Letby had injected air down a nasal gastric tube and this had led to the death of the three babies.
“This was repeated to the Court of Appeal, who may have been misled when they ruled on the application for leave against the convictions.”
He said Dr Evans had “revised his opinion in relation to Baby C” and had written a new report which he had given to police months ago.
But, he said “despite numerous requests” the prosecution had “yet to give this report to the defence”.
“The defence will argue that Dr Evans is not a reliable expert, and all the convictions are not safe,” Mr McDonald said.