Prince Harry’s lawyer has accused the Daily Mail’s parent company of “gaslighting” victims by covering up its journalists’ alleged illegal behaviour. The barrister David Sherborne alleged that Associated Newspapers publicly insisted it stuck to the law while privately knowing that reporters relied on a wide range of illegal techniques including voicemail interception, blagging of personal information, and placing listening devices inside cars. Associated denies the claims. Doreen Lawrence has alleged that a Daily Mail journalist instructed a private investigator to target her. She claims this took place at the same time as the Daily Mail was publicly campaigning on behalf of her murdered son, Stephen Lawrence. Sherborne told the high court in London: “That is nothing short of gaslighting Baroness Lawrence. That’s the concealment we are talking about.” Harry returned to the courtroom on Thursday to observe the closing legal arguments over whether his case will be allowed to proceed to trial. The case could drag the Daily Mail and Mail on Sunday into lengthy and expensive legal proceedings like those that have dogged the Sun, the News of the World and the Mirror over the past two decades. Harry and Lawrence are joined by Elton John, David Furnish, Sadie Frost, Elizabeth Hurley and Simon Hughes, the former Liberal Democrat MP, in bringing the legal action against Associated Newspapers. Sherborne told the court that the Daily Mail and Mail on Sunday hid their illegal behaviour by disguising the use of inappropriately obtained material in newspaper articles. The lawyer said the newspapers would print illegally gathered material in the form of quotes from “friends” of the victims, leaving individuals convinced that their inner circle had sold them out to the media. He said this tactic was tantamount to covering up crimes. “This creates the very paranoia and suspicion that leads people off the scent,” he said. Associated Newspapers strongly denies all the allegations as “preposterous smears” and is attempting to have the cases thrown out before they go to a full trial. The publisher told the court that Harry and his fellow claimants were “far too late” in filing their legal paperwork, meaning their cases should not be heard. Individuals generally have six years after discovering they were potential victims to bring a case. Associated argued that Harry and his fellow claimants should have known they were the potential victims of illegality by the Daily Mail and Mail on Sunday in the early 2010s, meaning they had missed the deadline to bring their case. In response, Sherborne said it was impossible for the cases to have been filed earlier because Harry and the other claimants only recently discovered they were potential victims. He also referenced “vociferous and prolific denials of any wrongdoing” made by senior executives at Associated Newspapers under oath to the Leveson inquiry into media ethics. Paul Dacre, the former Daily Mail editor, told the inquiry in 2012 that he was disgusted by phone hacking and other illegal behaviour by news journalists. He said under oath: “I can be as confident as any editor … that phone hacking was not practised at the Mail on Sunday or the Daily Mail.” Sherborne said Harry and the other individuals had wrongly believed Dacre. “Those denials were believed by a number of individuals who bring the claims,” he told the court. The judge Mr Justice Nicklin made several interventions that hinted he may allow the case to progress to the next stage. At one point he suggested that the reliability of witnesses would be best dealt with at a trial, which he said “could last a substantial period of time”. Nicklin said he would rule on the next stages “as soon as I can”. If the case does proceed, there will be lengthy pre-trial hearings over what material can be handed over before a full trial. Associated Newspapers has highlighted how some of the more detailed claims come from a witness statement in the name of a private investigator, Gavin Burrows, who appears to confess to carrying out multiple illegal acts on behalf of the Daily Mail and Mail on Sunday. Burrows has since provided a second witness statement to Associated in which he recants almost all his original accusations.