Press reform campaigners have welcomed the cross-party deal struck to bring in new regulation of the industry, saying they believed it "can effectively deliver" Lord Justice Leveson's recommendations.
Hacked Off said using a royal charter to back the new watchdog was the "second best" option but it believes the regulator will be "genuinely independent" under the newly announced measures.
Director Brian Cathcart told a press conference: "We believe charter is second best but we believe that this charter, endorsed by the three leading parties today, can effectively deliver his (Leveson's) proposals on self-regulation."
Prime Minister David Cameron will apply for an emergency debate in the House of Commons on the proposals for reforming press regulation, the Speaker's Office said.
The cross-party agreement was reached at around 2.30am on Monday, after five hours of talks between Cabinet Office Minister Oliver Letwin, Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband.
The deal bridges the gap between the Prime Minister, who insisted he would not accept a "press law", and Labour and Liberal Democrats, who wanted "statutory underpinning" to enshrine the new system in legislation. Under the terms of the deal, the terms of the new system of independent self-regulation of the press will be set out in a royal charter, rather than by legislation passed by Parliament.
However, a clause inserted into a Bill currently going through the House of Lords will give legislative backing to a safeguard within the charter, ensuring that it cannot be amended - either to water down regulation or to clamp down on the press - without the support of a two-thirds "super-majority" of both Houses of Parliament.
Lords will vote on the changes to the Enterprise and Regulatory Reform Bill later. The new clause does not explicitly refer to press regulation or the media or even to the royal charter itself. Instead, it states that no royal charter relating to an industry issued after March 1 this year may be changed unless the terms which it sets out for its own amendment have been met.
Conservatives gave ground on two key sticking points in the wording of the charter, which is expected to be published later. In its new form, the charter will not give the industry a veto over the membership of the board of the regulatory body. Members will be selected by a majority of an appointments board including representatives of the industry, rather than by unanimity, as proposed by Mr Cameron last week.
And it will give the regulator the power to "direct" newspapers on the size and positioning of apologies - strengthening the previous version's power to "require" them.
