The multimillionaire Brexit backer Arron Banks has accused Observer and Guardian journalist Carole Cadwalladr of “doubling down” on allegations she had made about his relationship with Russia since he lost a libel action against her. Banks was left in a “conundrum” where he was unable to restrain repetition of allegations about him, obtain damages or withdraw allegations made in a Ted Talk even though Cadwalladr had sent a private letter of apology, an appeal on behalf of the businessman was told. Cadwalladr had been sued by Banks, who funded the pro-Brexit Leave.EU campaign group, over two instances in which she said the businessman was lying about his relationship with the Russian state – one in a Ted Talk and the other in a tweet. While Cadwalladr did not argue that they were true, in a significant decision for public interest journalism, Mrs Justice Steyn ruled last July that the threshold for serious harm had only been met in the Ted Talk but that Cadwalladr initially had successfully established a public interest defence under section 4 of the Defamation Act. Benjamin Williams KC, for Banks, drew attention outside the appeal hearing to overnight tweets by the journalist, who had told her followers that the businessman would “try to overturn a minor point of the judgment against him” and that the high court had previously found he had a close and covert relationship with Russian officials in the run-up to Brexit. Counsel for the businessman told the three appeal court judges that this was further evidence that the judgment under appeal was unfair because Banks had been left without any remedy in respect of the mass publication of an exceptionally grave, but false, allegation that had caused him serious harm. Cadwalladr, he said, “had done nothing at all” to bring her previous concessions to public attention; both the tweet at the centre of the case and the Ted Talk remained live and she had continued to publicise it. Banks was watching the hearing from South Africa, where he was on business, said Williams, and accepted he was a “controversial figure who had thrown himself with gusto into the Brexit debate”. In fact, Williams said, both Cadwalladr and Banks “might be described as polarising, and even Marmite, in their public figures”, which came with a cost for both. For all the hearty debate around Brexit and the extent to which Banks had brought a diminished opinion upon himself “in some quarters”, Williams said there was a fundamental difference between how he was viewed by opponents in that debate “and being held as a cat’s paw” for a regime such as Russia. “Remember all of this happened after the Salisbury poisoning,” he added. In her judgment last year, Mrs Justice Steyn ruled that the journalist’s public interest defence under section 4 of the Defamation Act fell away after the Electoral Commission found no evidence of law-breaking by Banks with respect to his Brexit funding. But by that time – 29 April 2020 – the court was not satisfied that the continuing publication of the Ted Talk caused or was likely to cause serious harm to his reputation. Addressing the appeal hearing on Tuesday, Gavin Miller KC, for Cadwalladr, said that the judge’s reasoning was entirely consistent with core principles governing the tort of libel. Miller also addressed two other grounds on which Banks had sought permission to appeal – that the judge was wrong to find no serious harm in relation to Cadwalladr’s tweet after her Ted Talk and that it was wrong to find no serious harm regarding the Ted Talk itself after the change in circumstances brought about by the Electoral Commission findings in April 2020. In respect of these two other grounds on which Banks was seeking to appeal Mrs Justice Steyn’s ruling, Miller said: “They are thinly veiled attempts to relitigate matters which were ventilated in detail at trial and in respect of which the appellant disagrees with the judge’s conclusions.” Responding to other points raised by counsel for Banks, who sought to underline the extent of Cadwalladr’s reach on Twitter and retweets by her followers, Miller warned the three appeal court judges that it was difficult to precisely quantify the number of people who were coming afresh to the journalist’s original claim about Banks. Echoing Steyn’s finding, he said that the people who were looking at the Ted talk in the period after the public interest defence fell away were likely to be people who were doing that as supporters of Cadwalladr. “There is no evidence about who in this jurisdiction who had not seen it before is looking at it at this point. Sure, you can draw an inference about it but you have got to be really really careful about that. There is no particular reason to come to it afresh unless you are engaged in this particular debate.” In relation to Banks’s complaint that she had made no effort to remove the comments made in the Ted Talk, and its continuing presence online, Miller asserted that Cadwalladr’s was “not Ted” and it would be up to that organisation to “take down” the talk. Judgment in the case was reserved.