Former Labour leader Jeremy Corbyn is waiting to hear whether he has won the latest round of a court fight with a political blogger.
Mr Corbyn is trying to overturn a High Court judge’s ruling after being sued for defamation by Richard Millett.
He has mounted an appeal against preliminary findings made by Mr Justice Saini.
Three appeal judges considered arguments at a Court of Appeal hearing in London on Tuesday and said they would announce their decision on a date to be fixed.
Lawyers representing Mr Corbyn said the appeal raised “important and serious issues” about the right to freedom of expression of a senior politician.
Mr Millett has complained about things Mr Corbyn said in a BBC television interview with broadcaster Andrew Marr in September 2018.
He says Mr Corbyn defamed him by accusing him of being “disruptive and abusive” at a 2013 meeting featuring a Palestinian speaker.
Mr Corbyn, who says he was defending himself against charges of anti-Semitism, disputes Mr Millett’s claims and denies defaming him.
Mr Justice Saini made preliminary decisions about the meaning of words Mr Corbyn used – and about whether he was stating facts or expressing opinion – in July following a High Court hearing.
The judge concluded that Mr Corbyn was making “factual” allegations “as to Mr Millett’s behaviour”.
Lawyers representing Mr Millett argued that to accuse someone of being “disruptive and abusive to the degree in issue” must have “caused him to have been defamed”.
Lawyers representing Mr Corbyn disagreed and argued what had been said did not lower Mr Millett in the “estimation of right-thinking people”.
Mr Justice Saini concluded the “words complained of” referred to Mr Millett and “bore a meaning defamatory of Mr Millett”.
He said what had been stated suggested “conduct falling below the standards expected of citizens in modern British society”.
Anthony Hudson QC, who is representing Mr Corbyn, told Sir Geoffrey Vos, the Master of the Rolls, Dame Victoria Sharp, president of the Queen’s Bench Division of the High Court, and Lord Justice Warby that the case involved political and free speech, and required close scrutiny.
“This appeal raises important and serious issues about the right to freedom of expression of a senior politician in the context of discussion about a highly-charged and sensitive political issue, and in circumstances where he was defending himself against grave charges of anti-Semitism,” said Mr Hudson, in a written case outline.
“By his ruling, the judge has, amongst other things, denied Mr Corbyn the opportunity to rely on a statutory defence to a claim for libel which is fundamental to the protection of political speech, viz, the defence of honest opinion.
“The judge also erred in holding that statements which plainly did not meet the necessary seriousness threshold were defamatory at common law.”
He said Mr Justice Saini’s decisions amounted to a “serious interference” with Mr Corbyn’s human right to free speech.
Lawyers representing Mr Millett said Mr Corbyn’s appeal should be dismissed.
Mr Corbyn had said “the Zionists” who had attended the meeting had “berated” the Palestinian speaker.
He had said these “Zionists” did not want to study history and did not understand English irony.
In August 2018, when Mr Corbyn had become leader of the Labour Party, a video of that “irony speech” was made public.
Lawyers representing Mr Millett said there had subsequently been “huge publicity” about “the fact that” Mr Corbyn’s statements during the irony speech had been directed at Mr Millett.
Mr Marr had then asked Mr Corbyn about the “irony speech”, during an interview on The Andrew Marr Show, in September 2018.
Judges have heard how Mr Corbyn had told Mr Marr that he had not been “anti-Semitic”.
He said two people had been “incredibly disruptive” and he had accused them of not understanding English irony, because he wanted to defend the Palestinian speaker.
Mr Millett says people who had read media articles saying statements Mr Corbyn made during the “irony speech” were directed at him, and would have realised that the Labour leader was referring to him when telling Mr Marr about “two people” who had been “incredibly disruptive”.