The Duke of Sussex has reappeared at the High Court as his lawyers resisted an “ambitious” and “unattractive” bid by the publisher of the Daily Mail to end his legal action against it.

Harry and other high-profile individuals accuse Associated Newspapers Limited (ANL) of having “concealed wrongdoing” over the alleged unlawful gathering of their private information.

ANL, which denies the allegations, says a judge should rule in its favour without a trial because the legal challenges against it are brought “far too late”.

The publisher’s lawyers have argued the group, which includes Sir Elton John, his husband David Furnish and Baroness Lawrence of Clarendon, could have used “reasonable diligence” to discover they had a potential “worthwhile” claim earlier.

Lawyers for those bringing legal action say they were “thrown off the scent” and not aware of being targeted, having believed “categorical denials” from ANL over involvement in unlawful activity.

On the final day of a preliminary hearing in London on Thursday, David Sherborne, representing Harry and others, said ANL’s challenge to their legal action was as “ambitious as it is unattractive”.

He accused the publisher of seeking an “impermissible mini-trial or worse” before further documentation and evidence was secured in the cases.

The barrister said the group, which also includes actresses Sadie Frost and Liz Hurley and ex-Liberal Democrat MP Sir Simon Hughes, had a “compelling case”.

Mr Sherborne said ANL was alleged to have commissioned 19 different private investigators to carry out a series of unlawful acts from 1993 to 2011 and beyond, which in some instances informed articles.

He told the court the group was “thrown off the scent by the way in which the articles were written”.

Mr Sherborne later read out extracts from Baroness Lawrence’s witness statement in which she said she felt “played for a fool” by the Daily Mail, believing the newspaper “really cared” about the injustice of the murder of her son Stephen Lawrence.

The baroness said she learned a journalist allegedly instructed a private investigator to target her, saying that she “never thought to blame” the newspaper.

“They were supposed to be our allies and friends, the good people, not the bad,” she said, adding that she had believed that information in articles about her came from the police.

Mr Sherborne told the court: “That is nothing short of gaslighting Baroness Lawrence, that’s the form of concealment we are talking about.”

In written arguments, he added there were “vociferous and prolific denials of any wrongdoing by the defendant, made on oath to the Leveson Inquiry by its senior executives, and repeated ever since”, which the duke and others “were entitled to and did believe”, and which prevent the publisher from arguing that material could have been discovered earlier.

He said the group had since “uncovered concealed and systemic wrongdoing by the defendant” through information allegedly provided by private investigators and in new documents.

Mr Furnish, and later Baroness Lawrence, were also present in court again on Thursday, following visits this week from Sir Elton and Ms Frost.

Adrian Beltrami KC, for the publisher, previously told the court: “The claims are rejected by the defendant in their entirety as are the unfounded allegations that are repeatedly made that the defendant either misled the Leveson Inquiry or concealed evidence from the Leveson Inquiry.”

The lawyer said the legal action against it has “no real prospects of succeeding” and is “barred” under a legal period of limitation.

The duke and others allege that ANL hired private investigators to place listening devices inside cars, “blag” private records, and access and record private phone conversations.

Six of those bringing cases against the publisher have referred to alleged confessions by private investigator Gavin Burrows in their claims, but ANL has highlighted a later contrasting witness statement from Mr Burrows in which he denies being commissioned by its newspapers to conduct unlawful information gathering.

The hearing before Mr Justice Nicklin is due to conclude on Thursday, with a ruling expected at a later date.