Sub-prime mortgages, financial collapse, MPs expenses: these and other recent scandals are more than mere passing events. They have left Parliament and the market, the twin foundations of the free society, in disarray.

What has been lost is trust — our trust in those we chose to look after our affairs — and trust is the basis of society. If we are to recover it, we must ask some deep questions.

Thus far we have had a festival of blame, and there have been some sacrificial victims. But our great faiths teach the principle of collective responsibility. In that spirit we should ask what has gone wrong in society as a whole?

I believe we have lost our traditional sense of morality. I do not mean that we are less moral than our grandparents. We care about things they hardly thought about: world poverty, inequality, global warming and the loss of biodiversity. We are more tolerant than they were.

But note this: the things we care about are vast, distant, global, remote. They are problems that require the co-ordinated action of millions, perhaps billions of people. The difference we as individuals can make to any one of them is minimal. That does not mean they are not important: they are. But they are issues of politics, not of morality in the conventional sense.

When it comes to personal behaviour we have now come to believe that there is no right and wrong. Instead, there are choices. The market facilitates those choices. The State handles the consequences, picking up the pieces when they go wrong.

The idea that there may be things we would like to do and can afford to do but which we should not do, because they are dishonourable and a betrayal of trust, has come to seem outmoded.

In the case of MPs and financial institutions whole groups of people were, in effect, saying: “It’s legal, therefore it’s moral. Besides which, everyone else is doing it, so why shouldn’t I?” This was not a failure of individuals but of an entire culture, whose air we all breathe, and for which all of us share responsibility.

Concepts like duty, obligation, responsibility and honour have come to seem antiquated and irrelevant. Emotions like guilt, shame, contrition and remorse have been deleted from our vocabulary, for are we not all entitled to self-esteem? The still, small voice of conscience is rarely heard these days. Conscience has been outsourced, delegated away.

So, in place of an inner code, we have regulatory authorities. Where once people believed that God sees all we do, now we have CCTV and video surveillance. When self-imposed restraint disappears, external constraint must take its place. The result is that we have created the most regulated, intrusive society ever known.

And still it fails, and will always fail, because without a sense of responsibility to others, people will always find ways of outwitting the most sophisticated systems.

Two extraordinarily farsighted thinkers foresaw all this in the 1950s. The first was the American sociologist David Riesman, who argued that we were moving from an inner-directed society to an other-directed one.

An inner-directed society is one where people have an internalised sense of right and wrong. An other-directed society is one in which people take their cues from what other people do. Only in the latter can you have a situation in which people say: “If everyone else is doing it, it can’t be wrong.”

The second was the English philosopher Elizabeth Anscombe, who argued that morality had become incoherent because we had lost the foundation on which it was built. Words like obligation and ought belonged to a culture in which people believed that there was such a thing as a divine law: the belief shared by Jews, the Greek Stoics and Christians. Lose this and the words themselves lose their meaning. It is, she said, as if the word criminal remained when the criminal law had been abolished and forgotten.

If this is true, we face a much larger crisis than we think. Parliamentary reform and financial re-regulation will treat the symptoms not the cause. Without conscience there can be no trust. Without a shared moral code there can be no free society. Either we recover the moral sense or we will find, too late, that in the name of liberty, we have lost our freedom.

Rabbi Sir Jonathan Sacks is Chief Rabbi of the United Hebrew Congregations of the Commonwealth