Prince Harry was a “prime target” for the tabloid press and must have been a victim of phone hacking, his lawyer has told London’s High Court as the trial in the royal’s lawsuit against a newspaper publisher nears its end.

The prince and about 100 others are suing Mirror Group Newspapers, the publisher of the Daily Mirror, Sunday Mirror and Sunday People, over allegations of phone hacking and unlawful information gathering between 1991 and 2011.

They claim senior editors and executives at MGN knew about and approved of the wrongdoing.

MGN, owned by Reach, is fighting the lawsuit and says there is no evidence for the accusations.

The claimants’ lawyer, David Sherborne, told the court on Wednesday (British time) the case against MGN was “inferential”, stressing phone hacking and other unlawful information gathering was a covert practice.

He said the court could find Harry was a victim of phone hacking because of the prevalence of the practice at MGN newspapers and the level of press interest in the prince.

“The newspapers regarded him as a prime target, perhaps one of the most prime targets, in the sense of royal stories drive newspaper sales,” Sherborne said.

MGN has previously admitted its titles were involved in unlawful information gathering and has settled more than 600 claims, but says there is no evidence Harry’s phone was hacked.

It argues some of the personal information about Harry in stories cited during the case had come from or with the consent of, senior Buckingham Palace aides.

MGN’s lawyer Andrew Green said in court filings it was “highly unlikely” MGN would have targeted Harry, particularly after the 2006 arrest of the then-royal editor of Rupert Murdoch’s News of the World tabloid and a private investigator for accessing royal aides’ voicemails.

However, Mr Sherborne said the idea that MGN would not have “used every opportunity to obtain stories … is plainly implausible and they had the means to do so”.

On Tuesday, Mr Sherborne argued MGN’s failure to call its former employees, such as former Daily Mirror editor Piers Morgan, to give evidence was a fatal blow to its defence.

Morgan has always denied any knowledge of or involvement in wrongdoing and said after the trial started he would not “take lectures on privacy invasion from Prince Harry”.

Harry, the Duke of Sussex, became the first senior royal to give evidence in court for 130 years when he appeared this month for a day-and-a-half of questioning in the witness box.

The fifth in line to the throne said he believed phone hacking took place on an industrial scale at MGN’s titles.

MGN’s lawyer Mr Green argued in court filings Harry’s “undoubtedly fair resentment about his treatment by British and international media for many years” had been channelled into his legal action, which he said was not for compensation but part of his “campaign to ‘reform’ the British press”.

He said Harry’s lawsuit against MGN was “wildly overstated and substantially baseless”.

At the start of the trial in May, MGN admitted that on one occasion a private investigator had been engaged to unlawfully gather evidence about Harry.

However, it said he should receive no more than £500 ($958) in damages for that incident.

Mr Green was expected to begin making MGN’s closing arguments later on Wednesday, with the trial to conclude on Friday.