The pieces have settled again after the kaleidoscope was shaken 10 years ago. Tony Blair's hubristic ambition to "reorder this world around us" has not worked out the way he hoped, but certainly the world has changed, partly as a consequence of the slaughter of 11 September 2001. So where do we stand now? What is Britain's place in the world?

In most ways, the response of George Bush and Tony Blair to al-Qa'ida's attack was a wrong turning, and it has not been until the past few years that we saw a swing back to the more hopeful geopolitics of the period just before. As Rupert Cornwell writes today, the Bush administration was distracted for seven years from the growing problem of public and private debt in the US economy.

Mr Blair's immediate response to 9/11 was too slavish in its subjection to American policy, but there was an idealism about it too, some of which survives. There was even, in Mr Bush's desire to spread democracy as an end in itself, as well as a means to greater security for America and its allies, the germ of a noble idea. Sadly, its pursuit was naive, arrogant and morally compromised by torture and the abrogation of the very values for which the US-led coalition claimed to fight.

Looking back to his "kaleidoscope" speech in 2001, it is hard to recall the promise of a new ethical dimension to British foreign policy that Mr Blair offered. He restored our influence in Europe and rallied Nato to defeat attempted genocide in Kosovo.

Mr Blair spoke in that 2001 speech of "the starving, the wretched, the dispossessed, the ignorant, those living in want and squalor from the deserts of Northern Africa to the slums of Gaza, to the mountain ranges of Afghanistan: they too are our cause". They are words that ring hollow today.

A decade on, we have a far greater understanding of how hard such world-righting is. Starvation in Africa is still with us, in Somalia, for example, but, even as we renew our plea to you to join our Give a Day's Pay campaign, we can also say that the prospects for development in most African countries are better now than they have been since decolonialisation. And we should praise Mr Blair – and Gordon Brown – for their contribution to that.

As for the deserts of North Africa, they turned out to be more fertile soil for democracy than could have been imagined, and in Libya, where the idea of liberal intervention could be rescued and to an extent redeemed from the terrible mistake of Iraq. But the slums of Gaza and the mountain ranges of Afghanistan – as well as the sands of Mesopotamia – proved that reordering the world is much harder than fine words and good intentions.

Last week's report on the unlawful killing of Baha Mousa, the Iraqi civilian whose death was first reported by Robert Fisk in this newspaper in 2004, was a reminder of how much the Iraq war tarnished Britain's reputation abroad. So The Independent on Sunday's cautious support for our limited military intervention in Libya – with explicit UN authority and Arab League endorsement – is a measure of how much David Cameron has been able to recover from the mistake of his predecessor.

Yet Mr Cameron now faces some formidable tests. His visit to Russia tomorrow has been reduced to the status of a brief handshake accompanying a trade delegation, because of the coolness with which Vladimir Putin regards Britain. Yesterday's G7 summit in Marseille, attended by our Chancellor whose silly GQ speech demeaned the dignity of his office, showed how disunited the world is and how marginal Britain is in that debate. President Barack Obama's jobs plan goes in the opposite direction to Mr Osborne's austerity strategy, while William Hague, the Foreign Secretary, yesterday spoke of how Britain "may get ahead as a result of being outside" Europe's core.

Mr Cameron, on the other hand, has shown some skill in finessing his party's Euroscepticism and, by working with Nicolas Sarkozy in the Libya intervention, he has healed some of the diplomatic wounds of Iraq and learned those lessons. If he can extricate our forces from overstaying our mission in Afghanistan; if he can expunge the stain of British complicity in torture; and if he can make amends for British abuses of Iraqi civilians – then there is a hope that Britain, with a more realistic understanding of its capability, could regain some of the ethical role in the world that it lost after its mistaken response to 9/11.