Leveson reforms: Hugh Grant is anything but hacked off that new rules can curb the popular press

Fond as he is of Italian holidays, David Cameron promised he would never emulate Julius Caesar and "cross the Rubicon" – the stream outside Rimini which has come to symbolise a point of no return. On the other side of the Prime Minister's Rubicon was a new territory where the press was subject to statute, a prospect which – as senior figures in the newspaper industry reminded him – threatened a British tradition of free speech that dated back three centuries.

But from today there is an element of statute in press regulation – and David Cameron was the Prime Minister who brought it in.

A clause in the Enterprise and Regulatory Reform Bill – merely emphasising a point already made in the Royal Charter itself – is hardly a press law. Papers including the Financial Times, The Independent and The Guardian had already signalled their willingness to accept such a clause as part of the implementation of the Leveson proposals. Those papers appear comparatively relaxed about the development.

This merest hint of statutory underpinning – and the Tories were unwilling to even recognise it as such – was the absolute minimum that the more vociferous victims of the press abuses which prompted the Leveson Inquiry were willing to contemplate.

But the signs are that Mr Cameron's solution to press reform will be too much to bear for some newspaper groups, who see their brands of popular journalism as threatened, not so much by the element of statute as by the last-minute concessions that the Conservatives made to Labour and the Liberal Democrats.

The new press regulator will have the powers to order front-page apologies as well as impose £1m fines. And newspapers will not be able to block the appointment to the regulator of any individual who they regard as hostile to their interests – such as a supporter of the press reform group Hacked Off.

The fact that Hugh Grant's team signalled its delight with the outcome – and that the lobby group was present alongside political leaders at the final late-night discussions – will gall those newspaper businesses who believed Mr Cameron was assisting the industry in establishing a system of self-regulation.

The three political parties each spent yesterday claiming to have triumphed. But if the Prime Minister has won any kind of victory it is at a cost of taking him into territory where previous allies could become dangerous enemies.