Prime Minister David Cameron and his deputy Nick Clegg have unveiled rival plans for a new system of press regulation in England and Wales.

The two sides have moved closer together, but the major sticking point remains - whether a new self-regulatory body should be backed by law.

Mr Clegg's royal charter, launched with Ed Miliband, insists on it - but it is not in Mr Cameron's royal charter.

MPs will decide which version they prefer on Monday.

The vote is expected to be close - and could have a profound impact on the way newspapers conduct themselves in the wake of the phone-hacking scandal and Lord Justice Leveson's inquiry.

Both sides have now adopted the idea of a royal charter - a formal document used to set up bodies such as universities and the BBC.

But the key differences between the two plans are:

Legal backing - Mr Cameron believes enshrining the royal charter in law will harm press freedom. Mr Clegg and Mr Miliband say the rules will lack teeth without it.

Power of veto - The press would not have a veto over the members of the regulator under the Lib Dem/Labour plan.

Future alterations - The Labour/Lib Dem plan is designed to prevent it from being watered down or strengthened by future governments.

An expert report on the regulation of the press in Scotland has recommended statutory controls underpinned by law. First Minister Alex Salmond has said he will consult other parties before deciding on action.

'Crucial'

Lib Dem leader Nick Clegg said the blueprint he had drawn up with Mr Miliband represented a "strengthened version" of earlier proposals set out last month by the Conservatives and he hoped MPs on all sides could back it.

"I hope the approach we are publishing today plots a middle course between the dangers of doing nothing and the fears some people have of a full-scale legislative approach," said the deputy PM.

Media playback is unsupported on your device Media caption David Cameron on the importance of 'conclusion' on the issue

Mr Miliband said the proposals would ensure "a high ethical standards of the best in British journalism; a complaints procedure which is easily accessible and fair; and real teeth to ensure protection and redress for citizens".

Mr Clegg and Mr Miliband formed their alliance on press regulation after Mr Cameron walked out of cross-party talks on Thursday.

The Conservatives have published amendments to the Crime and Courts Bill which would allow the courts to impose "exemplary damages" - large fines - on publishers of "news-related material" which is inaccurate or intrusive.

The threat would be lifted from publishers that sign up to an approved regulator, creating an incentive for newspapers to engage with the new system.

'Bills hijacked'

Mr Cameron believes his proposals will defend press freedom and provide swift justice for victims of press inaccuracy and intrusion.

He has toughened up his proposals in some key areas - the regulator would now have the power to dictate the prominence of a printed apology and the arbitration process would be free to complainants.

But he must now convince Tory rebels - who are planning to vote against his proposals - that his royal charter are robust enough.

Media playback is unsupported on your device Media caption Labour leader Ed Miliband: ''We want a system of redress for victims''

He defended his decision to walk out of cross-party talks on Thursday, saying he wanted to force the issue to a head and he believed a deal could still be reached.

"We can't go on with a situation where bill after bill of the government's legislative programme is potentially hijacked or contaminated with motions and amendments that are about something that is completely different," he said.

"That's why I think it is right to bring this to a conclusion."

Gerry McCann, the father of missing Madeleine McCann, said it was essential that the regulator was backed by legislation.

"Lord Justice Leveson was absolutely clear on this. He said that statutory underpinning was essential," he told BBC News.

"Up until the announcement I had never really heard of a royal charter. It seems something of an archaic system to underwrite something so important.

"I would much, much prefer that this was put properly into the statute book."

The Leveson Inquiry was set up by Mr Cameron to examine the culture, practice and ethics of the press in the wake of the phone-hacking scandal at the now-defunct News of the World tabloid.

Its 2,000-page report, published in November, found press behaviour was "outrageous" and "wreaked havoc with the lives of innocent people".

It recommended that the press should set up a tough new independent regulator, but the system should be underpinned by legislation to ensure the system was effective.

Downing Street insists the bust-up between the prime minister and his deputy over press regulation does not spell the end for the coalition government.

The prime minister's official spokesman said it was "not the first time that coalition parties have taken a different approach on important but specific issues".

Mr Clegg said he was "disappointed and surprised" Mr Cameron had walked out of Thursday's talks, but he said he had always taken a separate position from the PM on whether press regulation should be backed by law.