A common feature of like-minded individuals, say cyclists or dog walkers, is mutual recognition. Perhaps through a word, a nod or an agreeable wave. And why wouldn’t it be so? It’s a fundamental part of the human condition to find comfort, solidarity and security in those whose choices mirror our own.

One friend tells a story of being driven home from hospital by her husband after undergoing rhinoplasty (or what, in old money, used to be brutally referred to as a “nose job”). As the couple drew up at the traffic lights, my friend turned to see a woman in the passenger seat of the adjacent car whose nose was also bandaged in the same, singular way; she too had been under the knife.

Feeling a sense of kinship, my friend gave a shy wave to the stranger, semaphore for “Ooh, you too”. For which she received a delicate nod of the head and gauzy smile in return (not easy when your snout is packed like an Amazon delivery). It was acknowledgement of the same shared experience.

Of course, as Jews, we don’t need bike rides or plastic surgery to find reason to greet complete strangers. Shabbat gifts us the perfect opportunity to acknowledge our fellow Jews. It even comes with a ready-made, two-word greeting.

Certainly, stepping outdoors on a Shabbat in my corner of North Manchester, perambulating Jews can be sure of receiving, at the very least, a polite or more likely sunny “good Shabbos” — from mothers shepherding truculent toddlers in their Sabbath best to the tardy congregant marching purposefully to pray, having unintentionally slept late following an especially leaden Friday night dinner.

Yet when I visit North London’s borscht belt I find it astonishing that so many Jews pass me by without such a greeting (unless I blink first). At best, unprompted, there might be a slight nod. Otherwise there appears to be a deliberate effort not to engage — to look hazily into the middle distance as if, like Vasco da Gama, the mind is preoccupied with the idea of new worlds to conquer in darkest Finchley, Temple Fortune, Hendon and Golders Green.

Those who do make eye contact reflect in their expression a bafflement that personal reveries should have been interrupted by a complete stranger — even though, in generations past we may have even been born in the same shtiebel.

I should at this stage stress that this is no reflection on the hospitality offered in these parts. With two children living in the capital having married gorgeous London girls, as well as a son who studied at university in London, I know of repeated invitations for Shabbat meals and a willingness to offer warming food and conviviality to out-of-towners. I hear it too from friends whose children have migrated south and who have also been looked after this way. The benevolent matriarchs of North London more than equal those of North Manchester.

Yet out on the streets of London, where far less effort is required, Shabbat greetings fall silent: a Jewish version of Ralph McTell’s eponymous hit. “It’s just not done,” one London friend tells me, who also acknowledges that the blizzard of greetings when visiting Manchester is as strange as it is overwhelming. “It’s not in the DNA.”

A suggestion then of British stiff upper lip, kosher style or simply a self-fulfilling prophecy — because it’s never been done, it’s never done?

Ironic really, since our history of displacement and relocation has meant Jews have evolved to be adaptable and to find ways to connect with our brethren as a form of security. My husband loves nothing better than sparking a conversation with strangers who are Jewish, most recently in the queues for Westminster Hall, the day before the Queen’s funeral, where he spotted a group of sheitel-wearing women and immediately asked them if they were returning the following morning for the leviaya (they were delightful and, typically, we soon found mutual connections — not with royalty — because of our shared lineage, even though we’d never met before).

Given that we are so good at creating links with complete Jewish strangers, wouldn’t it be nice if the — literally — unspoken default position of Jewish London was broken with a gutsy “Shabbat Shalom” to fellow brethren (only on a Saturday, of course).

What’s to lose? Nothing. But the gains will be bountiful. A feeling of warmth and connectivity. An enhancement of the shabbat experience. A chance to unite.

To subvert a riff on that great Mancunian saying: come and have a go, if you’re soft enough. You won’t regret it. Shabbat shalom.