An inquiry into British press ethics set up in response to a phone-hacking scandal at Rupert Murdoch's News of the World could be curtailed or severely delayed to allow time for possible criminal prosecutions, the presiding judge said.
The need to wait until any prosecutions are out of the way could put the inquiry on hold for several months if not longer, Brian Leveson wrote on the inquiry website.
The Leveson inquiry was split into two parts: the first dealing broadly with the way news organisations operate, and the second looking at how much they might have broken the law.
A spokesman for the inquiry said the Part 1 recommendations would not be delayed and would be published in October.
"The key work of the Inquiry in Part 1 - producing recommendations on future regulation of the press - will not be affected," the spokesman said.
So far, Part 1 has dealt with issues concerning the press and the public and the press and the police. It is now about to look at relations between the press and politicians.
The second stage was always going to have to wait until after any prosecutions over phone-hacking or police corruption to avoid possibly prejudicing the trials.
The number of arrests has risen inexorably in the scandal and police are having to trawl through a mountain of emails relating to the various cases.
So far over 40 people have been arrested, including two former editors of the now-defunct News of the World, and prosecutors are considering whether to charge 11 suspects.
Leveson wrote: "I do not know whether there will be prosecutions but, having regard to the number of arrests and the quantity of material seized (including the 300 million e-mails which it is said have had to be analysed) ... it is likely that the process of pre-trial disclosure and trial will be lengthy so that Part 2 of this Inquiry will be delayed for very many months if not longer.
"In those circumstances, it seems to me that it is in everyone's interests that Part 1 goes as far as it possibly can."
Part 2, Leveson warned, would be very expensive, would be looking at evidence that could by then be even more out of date and would go on longer than Part 1, which began last November.
The Leveson proceedings are separate from another inquiry into phone-hacking by parliament's Culture, Media and Sport Committee, which concluded on Tuesday that Murdoch was unfit to run a major international company.
Satellite broadcaster BSkyB sought to distance itself from the hacking row at Murdoch's News Corp, its biggest shareholder, after British lawmakers suggested BSkyB's ties to News Corp might jeopardise its license.
