Riots and bankers' greed have sent Britain's communities spinning apart in the dark this year, the head of the Church of England will say in his Christmas Day sermon, warning against building a society on foundations of selfishness and fear.

Rioting and looting erupted across England this summer, leaving some towns ransacked and divided, while public anger against irresponsible behaviour and big bonuses in the banking sector has remained strong throughout the financial crisis.

The most pressing question we now face, we might well say, is who and where we are as a society. Bonds have been broken, trust abused and lost, Archbishop of Canterbury Rowan Williams will say at Canterbury Cathedral on Sunday, according to extracts released in advance by his office.

Whether it is an urban rioter mindlessly burning down a small shop that serves his community, or a speculator turning his back on the question of who bears the ultimate cost for his acquisitive adventures in the virtual reality of today's financial world, the picture is of atoms spinning apart in the dark.

Williams, the spiritual leader for 77 million Anglicans around the world, told the Conservative-led coalition government earlier in December to consider the social impact of its austerity drive, particularly in cuts to youth services.

He warned that Britain could face more riots unless communities and the authorities did more to reach out to disenfranchised young people.

Williams, no stranger to courting controversy with his remarks about politics, fairness in society and morality in global affairs, has also previously said the wealthy are not bearing their fair share of spending cuts.

He has criticised the government for acting radically without a mandate, has backed the anti-capitalist protesters who camped outside St Paul's Cathedral in central London and supported calls for a Robin Hood tax on the banks.

Britain has been in the economic doldrums since the credit crunch hit in 2008/9. Despite showing signs of recovering from its worst recession since World War Two, the economy is now teetering on the edge of another period of contraction.

Unemployment is rising and the government is slashing public spending and shedding jobs in the public sector to reduce a record budget deficit, while struggling to engineer a private-sector-led recovery.

With inflation rising much faster than average earnings, households are seeing their standards of living falling, leaving many to question how bankers - often blamed for triggering the global crisis - can still receive huge pay packets and bonuses.

Are you on your own side, on the side of disconnection, rivalry, the hoarding of gifts, the obsession with control? Williams, who has faced splits and divisions in his own church over gay rights and female bishops, will ask in his sermon.

In the darkness the questions sounds as clear as ever, to each of us and to our church and our society: 'Britain, where are you?' Where are the words we can use to answer?

(Editing by Jon Hemming)