Andrew Grice: Miliband must switch focus from Tripoli to London to gain capital

Inside Westminster

David Cameron has had a good war in Libya.

Although it is not over yet, the minds of Conservative MPs are already turning back to what they regard as the Government's immediate priority – ensuring peace on the streets of Britain rather than Tripoli.

The riots may have fizzled out in the face of a massive police presence, but they could happen again. Even if they do not, they will shape the British political debate for some time. True, the state of the UK economy will probably be the biggest factor at the next general election. Ministers are privately relieved that an unusually newsy August – phone hacking, riots, Libya, the eurozone crisis – ensured the anaemic growth at home did not fill the media vacuum. Its time in the spotlight will come.

The riots are a seismic event from which the political caravan will not be able to move quickly on. Tory MPs will hold Mr Cameron to his tough words on law and order. Many have been waiting a long time to hear them from him; they never liked "hug a hoodie". As one senior Conservative said: "We cannot afford a repeat of such anarchy on our streets; we would be finished as a government." For other Tories, the prize is to ensure the Prime Minister seizes a unique opportunity to use his flagship "big society" idea to fix "broken Britain".

Mr Cameron believes in this agenda passionately and must now summon the energy to ensure it is taken more seriously right across government. Many ministers and civil servants roll their eyes when they hear the words "big society" and you won't catch Nick Clegg using them.

There are risks as well as opportunities for Mr Cameron. Reaching for a familiar soundbite about "broken Britain" was a natural reaction to this month's dramatic events. "Broken society" was a phrase he used a lot in opposition. In government, "broken Britain" was quietly dropped, presumably because it sent a negative, pessimistic signal. There were enough of those around already.

Mr Cameron is setting the bar high. And this time he is setting it for himself rather than for a Labour administration while he enjoys the luxury of opposition.

Fixing a "broken society" is a million times harder than broken windows. How do you change the values of those who joined the riots? Surely, not by preaching to them. Of course the country's 120,000 problem families need to be targeted through early intervention and "tough love". But even if many of these families were turned around – a big "if"– it would not necessarily prevent another outbreak of "grab what you can, while you can" opportunism in our shopping centres and high streets.

The politicians need to take a look at themselves and the circles in which they move as well as the rioters if they want to understand why this happened. It is not to condone or excuse criminality to say that many of those rioting may have detected a "grab what you can" culture among MPs in the expenses scandal and the bankers who brought us the financial crisis.

Ed Miliband grasped this point. He resisted the temptation to blame the troubles on poverty or the cuts. Like Mr Cameron, he had spoken about the need for greater "responsibility" well before the riots. But the Labour leader has been clearer about the need for responsibility by politicians, bankers and the media as well as the poor. As he put it after the disturbances: "People who talk about the sick behaviour of those without power, should talk equally about the sick behaviour of those with power."

The riots have fuelled an already intense debate in the Labour high command about how to oppose Mr Cameron. Once the Tories agonised over whether Tony Blair was "Bambi" or had "demon eyes". Today Labour is not sure whether to portray Mr Cameron as a slick but untrustworthy PR man selling a still dodgy Tory brand, or a wolf in sheep's clothing who poses as a moderniser to hide a right-wing agenda on cuts, welfare and health reforms that even Margaret Thatcher baulked at.

Mr Cameron's tough law-and-order line after the riots may tip the balance in favour of those who want to attack the Prime Minister as a "son of Thatcher" keen to complete her unfinished business. There are dangers in this approach for Mr Miliband. It might leave his party open to the Tory charge of being "soft" on crime, something Mr Blair was always desperate to avoid.

Mr Miliband, who has grown in confidence since the phone-hacking scandal, worries less about hostile headlines in right-wing newspapers after standing up to the Murdoch empire. He believes the rules of the game have changed since the Blair era.

We may be about to find out whether he is right.