Leading article: We need real reform, not just consensus

This is a decisive week in British politics, the moment when the new Tory-Liberal Democrat coalition faces its first real test. It starts with the £6bn to be found in spending cuts, announced today. This will be a minor surgical incision compared to the savage exercise in knife-wielding the country can expect in the autumn. Nevertheless, as the two governing parties are forced to move on from popular rhetoric about what they intend to protect to the less popular business of what they intend to cut, hairline cracks will start to emerge.

Then tomorrow we have the Queen's Speech, when the new Government sets out its agenda. This presents other challenges. It is vital to the coalition's long-term prospects that it proves it can do more than articulate policies that neither of their parties disagrees with. Above all, the onus is on the Liberal Democrats to prove to the country, and to the many doubters inside their own party, that they are not there primarily to serve David Cameron's various purposes, one of which is to use the coalition to muzzle the Tory right.

Liberal Democrats have to demonstrate that they can exert substantive influence over policy, and do it fast, for the experience of all governments – this certainly applied to New Labour from 1997 to 2010 – is that reforming zeal soon fades. So far, the omens for the Queen's Speech are good. Identity cards were a rotten idea, so we welcome their consignment to the dustbin of history. An ill-conceived example of gesture politics, their introduction would only have added layers of bureaucracy to people's lives, while the case for the defence, which is that they would improve national security, was never plausible. A reform Bill incorporating fixed-term parliaments and a referendum on changes to the system of voting in Westminster elections is also encouraging, another sign that "change" was more than an anodyne campaign slogan.

The bigger question is whether these initial commitments and noises about greater freedom, welcome as they are, go on to form the building blocks of broader reforms to the constitution, civil liberties and to education – the latter the most shameful failure of the Labour era, given Tony Blair's promise to put it at the very heart of his government.

Scrapping identity cards will, of course, save money. Changes to permit Swedish-style academies – the Education Secretary Michael Gove's idée fixe – and establishing fixed terms for parliaments won't cost much. The bigger immediate headache for the Tories and the Liberal Democrats is where jointly to wield the axe. This will be especially challenging given that both parties campaigned in the election on money they intended to give away and on frontline services that they intended to protect.

The Prime Minister won't lose much sleep over having to sacrifice tax breaks for married couples, a foolish attempt at social engineering. But the potential savings to be made here are paltry. The same goes for scrapping the promise to raise the inheritance tax threshold. The problems will start elsewhere, if the much talked-of bonfire of quangos fails to yield the billions anticipated. And we must not forget this is only the prelude; much deeper cuts are round the corner.

Of the two party leaders, Nick Clegg faces the rougher ride. Core Tory voters are not unduly bothered by cuts and indeed may welcome them, wherever they fall. By contrast, cuts go against the grain of the Liberal Democrats. Out of power for as long as anyone can remember, it's been their privilege not to have to think about such matters. This is now about to change.

The most unusual partnership in modern British politics may come through this week unscathed; it would be a surprise if it didn't. But underlying strains in the coalition have not been quelled, and as cuts start to bite, will emerge sooner or later.