The Duke of Sussex should be awarded up to £500 in damages for one admitted instance of unlawful information gathering, The Mirror’s publisher has told the High Court.

Several high-profile figures are suing Mirror Group Newspapers (MGN) over alleged unlawful information gathering at its titles, claiming journalists at the tabloids were linked to methods including phone hacking, so-called “blagging” or gaining information by deception, and use of private investigators for unlawful activities.

Four “representative” claimants, including Harry, have given evidence during the seven-week trial.

MGN, publisher of titles including The Mirror, Sunday Mirror and Sunday People, is largely contesting the claims, arguing that some have been brought too late.

As closing arguments began on Tuesday, Andrew Green KC, for MGN, said in written submissions that the “vast majority” of payment records to third parties either do not concern Harry, do not concern unlawful information gathering, relate to legitimate inquiries or do not relate to articles in the duke’s claim.

However, establishing that an individual is a victim of general and widespread media intrusion leading to negative effects at the hands of the press is not the same as demonstrating that he/she is a victim of unlawful voicemail interception and other unlawful information gathering by three specific newspaper titles

Mr Green said: “There is only one occasion of admitted unlawful information gathering in respect of the Duke of Sussex, in February 2004.”

He continued: “In this case the Duke of Sussex should be awarded a maximum of £500, given the single invoice naming him concerns inquiries on an isolated occasion, and the small sum on the invoice (£75) suggests inquiries were limited.”

At the start of the trial in May, Mr Green said the publisher “unreservedly apologises” to the duke for this occasion and that it accepts he was entitled to “appropriate compensation”.

The barrister said that it was admitted that a private investigator was instructed, by an MGN journalist at The People, to unlawfully gather information about his activities at the Chinawhite nightclub one night in February 2004.

He told the court: “MGN does not know what information this related to, although it clearly had some connection with his conduct at the nightclub.”

“Otherwise, the specified allegations are denied, or in a few cases not admitted,” he added.

The barrister said that there was a People article published in February 2004 “giving the recollection of a woman Harry spent time with” at the club.

Mr Green later told the High Court this was not one of the 33 articles selected for trial in Harry’s claim, “so it is not alleged that this instruction led to the publication of his private information”.

Addressing these 33 articles in his written closing submissions, Mr Green said the evidence does not suggest they were written as a result of unlawful activity and therefore Harry is not entitled to damages.

The barrister added: “If, contrary to MGN’s position, the court finds that any of the articles were the product of unlawful activity, we have included… the appropriate award for the articles.

“In most instances that is still zero: this was simply not the Duke of Sussex’s private information.”

These suggested figures for potential awards, if they were found to be products of unlawful information gathering, include up to £5,000 for an article in 2000 about an injury Harry had suffered.

In his written closing submissions, Mr Green later said that the duke was not entitled to damages for distress and that he had not identified “specific distress” caused by alleged unlawful acts by MGN.

“He was able only to identity upset and anger at the general intrusion he faced by every media outlet, nationally and internationally, over many years,” the barrister said.

Mr Green added there was no basis to find the duke was a victim of phone hacking “either on an occasional basis, habitual basis, or even on one occasion”.

The barrister also said: “It is impossible not to have enormous sympathy for the Duke of Sussex, in view of the extraordinary degree of media intrusion he has been subject to throughout his life due to his position in society.

“However, establishing that an individual is a victim of general and widespread media intrusion leading to negative effects at the hands of the press is not the same as demonstrating that he/she is a victim of unlawful voicemail interception and other unlawful information gathering by three specific newspaper titles.”

As well as the duke, the other “representative” claimants are actor Michael Turner, known professionally as Michael Le Vell, best known for playing Kevin Webster in Coronation Street, actress Nikki Sanderson and comedian Paul Whitehouse’s ex-wife Fiona Wightman.