Important matters of public interest are likely to be aired in a trial that has been brought against the Guardian and the BBC for their reporting of the Paradise Papers investigation, a senior judge has said.

Mr Justice Vos, who heads the chancery division of the high court, said it would take a five-day hearing to examine the issues raised by the project, which relied in part on documents from the offshore law firm Appleby.

The company has been seeking to force the Guardian and the BBC to disclose the documents they used for their investigations, which caused global debate when they were published last November.

But Appleby’s application for this disclosure at a hearing on Wednesday was described as “premature” by the judge, who set a date for a trial in September.

Both media organisations are the subject of breach of confidence proceedings and a request for damages by Appleby.

It has claimed that millions of its documents were stolen in a cyber-hack and has demanded the disclosure of any of those that informed reporting for a project that drew attention to the tax dodges used by individuals and companies.

Vos referenced plans by the government to force Britain’s overseas territories to adopt public registers of company ownership.

“We know what parliament has decided. We have seen it in all of the newspapers this morning,” he said.

The judge also noted that the issues had been the subject of coverage by “multiple news organisations all over the world”.

Hugh Tomlinson QC, for Appleby, said the firm accepted that it was in the public interest to discuss certain issues.

He cited offshore accounts, preferential rates, trust structures that enable people to avoid tax.

However, he added that it was not always the case that there was a public interest in revealing financial affairs in every circumstance – any more than it was to “expose” people’s private health records.

Tomlinson said Appleby accepted there had been an engagement by the media organisations of article 10 of the European convention on human rights, which provides the right to freedom of expression and information, but added that this was at the “outer limit”.

“The fact that it’s the right of freedom of expression does not turn it into some special or unique case. It’s just another factor to consider,” he said.

“The position is that they have our documents. We are under pressure from people to explain what is going on and we cannot.”

The documents were leaked to the German newspaper Süddeutsche Zeitung, which shared them with a US-based organisation, the Pulitzer prize-winning International Consortium of Investigative Journalists (ICIJ).

The ICIJ coordinated the Paradise Papers project, which included 380 journalists from 96 media organisations across 67 countries. The consortium included the New York Times, Le Monde, the ABC in Australia and CBC News in Canada.

The project revealed details of the complex arrangements and offshore activities of some of the world’s richest people and companies.

Delivering his judgment, Vos said he was ordering a “speedy” trial to start in September so that the issues could be resolved. All parties had agreed to this course of action.

On disclosures, he said it was clear to him that the BBC must be in a position to disclose the documents which it had accessed via a database if ordered to do so. For the purposes of the trial, however, it would be necessary for the documents to be disclosed in a “confidentiality club” arrangement that would be accessed by lawyers from both sides so that they could decide that what was being said about them was correct.

On the question of whether the documents disclosed should also include “journalistic content”, he said that that this would depend on the type of material.

Internal communications about journalistic style would not, but a document expressing a view about the public interest of certain material might, said the judge.

Appleby’s group managing partner, Michael O’Connell, said: “These directions, and the urgency injected into the process by the chancellor, are welcomed by Appleby. It means that our grievances can be properly heard and the situation can be resolved as swiftly as possible and this is consistent with our objectives in bringing this legal action. The early disclosure process that has been ordered is particularly valuable.”