It takes a brave man today to publish a book with the title Morality – or a foolish one. In the current climate, it runs the risk of sounding preachy, or else being an adornment to the virtue-signalling, intolerant culture that thrives on social media, where you are either with us or against us.

But, then, Jonathan Sacks, former chief rabbi of Great Britain and the Commonwealth, now Lord Sacks of Aldgate, has never been short of courage in speaking his mind in the wider public arena, even when his thoughts run counter to the orthodoxy of the moment. An earlier book, The Dignity of Difference, provoked the ire of some of his fellow rabbis by stating that, “no one creed has a monopoly on spiritual trust” (a remark that was removed in later editions).

And he has been clear and counter-cultural in opposing same-sex marriage. “In Judaism,” he stated, “we don’t do it.”

Given the new book’s title – “morality is a very, very difficult word”, he acknowledges, almost with relish – its contents will come as a disappointment for those expecting a traditional list of “don’ts”.

This is not, its author is keen to stress, “about going boldly in reverse back to Victorian England”. Don’ts, he suggests, “are what you say when you see someone else enjoying themselves”. And therefore want to stop them. Rabbi Sacks, though, is not one of nature’s killjoys.

Instead, what made him put pen to paper on morality was his sense that the West is in “dark” times. His diagnosis is that we have lost sight as a society of the “we” – the common good – because we have been seduced by the “I” of individualism.

“I just felt,” he explains, “that I ought to point out what happens when you let go of morality.”

We are sitting in the home in Golders Green, north-west London, that this 71-year-old father of three and grandfather of nine shares with his wife of 50 years, Elaine. As he is talking, Rabbi Sacks radiates an almost prophetic sense of calm purpose and clear-sightedness.

It is a quality that has won him a legion of admirers beyond his own Jewish community. The Prince of Wales has referred to him as “a light unto this nation”, while the Today programme’s Nick Robinson says he is one of the very few Thought for the Day contributors he bothers to listen to when they come into the studio.

The loss of a sense of “we” – what Sacks calls, in a resonant phrase, cultural climate change – was caused, he says, by three “hammer blows”. First, the social revolution of the 1960s. Then, the economic upheaval of the 1980s which lead to Michael Douglas in Wall Street declaring that “greed is good”. And finally, the social media revolution, “and its focus on presentation of self”.

None is bad in and of itself, he adds, but their consequences can be. With social media, too many users are anxious, he says, to claim the moral high ground at the same time as vilifying those with other views.

When I mention the current fashion to call out every perceived injustice or intolerance and the new ‘cancel culture’, which seeks to silence anyone who doesn’t think in the ‘right’ way, he breaks into a smile. “It is a very selectivist form of morality. You think you can change the world by pressing a like/dislike button. It is armchair morality. It is too easy.”

It is part, he fears, of a broader drift towards identity politics – the “groupishness” that seeks only to speak to the like-minded and then demonise every one else. “There is,” he cautions, “a phrase in the opening to the preamble of the US constitution: ‘We, the people’. The team is bigger than the player, and the game is bigger than the team. We have lost a sense of what binds us together as a nation.”

He is equally unimpressed by “no-platforming” in our universities, where those whose views don’t fit specific groups’ notions of what is acceptable are banned for speaking on campus. It is a fate that has befallen Germaine Greer and Fay Weldon because of their views on trans women, and more recently Oxford academic, Professor Selina Todd, whose invitation to a conference celebrating women was last week withdrawn after a campaign by transgender activists.

Last week, former home secretary Amber Rudd had her own Oxford appearance, at an event promoting women in politics, called off at last minute amid a row about her links with the Windrush scandal.

“There is this new concept of safe space where you are to be protected from views that may be hurtful to you. I have exactly the opposite definition of safe space. Not mocking, but challenging. Listening respectfully. That is what university should be about. You listen to views opposed to your own because you know that the people opposed to you will listen respectfully to you.”

All these trends contribute to the switch for “we” to “I” in what he nevertheless continues to see in Britain as, at heart, an inclusive society. Even, I wonder, after the Labour Party leadership’s recent drift into anti-Semitism?

“The appearance of anti-Semitism in any society is an early warning sign of deeper breakdown,” he replies, “which is why it is serious. It touched every member of our community, including those who were never particularly affiliated or public about their identity. I have never seen them so anxious, or so relieved [by an election result].”