By and large I’ve found that a good rule of thumb for gift giving is to go for small and often. You don’t want to scream ostentatious (which says more about you, and the extent of your disposable income, than how much you value whoever you’re giving to). And you don’t want to give anything too valuable and risk creating an anxiety over social debt. A drip, drip approach lets the recipient know they are valued without qualification and without creating any expectation of repayment.

That, at least, is the theory. For these are delicate negotiations. Their rules are unspoken and their sensitivities potentially explosive.

Gift giving and receiving is a very particular transaction. It involves a complex coding of value and obligation in which a price gets placed on esteem and a burden of debt is transferred from giver to recipient. If the esteem is valued too low, or the burden of debt too high, the gift may be taken for an insult. Conversely, if the esteem a gift honours is over-valued, or the burden of debt is too lightly waived aside, the gift will cause embarrassment.

Jhumpa Lahiri’s The Real Durwan is short story of cunning complexity that exposes the string-pulling dynamics behind gift giving among a group of apparent social equals living in Calcutta tenement. The residents are neither wealthy nor especially poor; but diligent, white-collar workers, struggling to get along, and with the usual run of material aspirations tempered with a dollop of social conscience. Between them, they employ a caretaker, Boori Ma, a woman of pensionable age who has fallen on hard times since partition.

Boori Ma sweeps the stairwell of the tenement and patrols the alley by day, then sleeps behind the collapsible gate, as if guarding the tenants from the outside world.  Although this is no job for a woman, least of all one in her sixties, Boori Ma goes about her duties with pride and vigilance. That she is valued by the tenants is beyond dispute: they invite her into their homes, give her tea and crackers, and loan her medicines, while she helps entertain their children.

The delicate ecosystem of the building is however disturbed when one day one of the tenants, celebrating a promotion at work, brings home two small ceramic basins. He fixes one in his flat, where it becomes a mark of civilized distinction (a private basin!), and one on the stairwell, so the rest of the residents can avail themselves of the new luxury.

The basin’s arrival is initially greeted with joy as the tenants line up to brush their teeth with fresh running water, instead of using water reserved in a mug from the day before. But they soon get shirty about not being able to leave their toothbrushes on the basin’s rim, as they would if they didn’t have to share it. And they tire of waiting in line like children. Soon they begin to resent Mr Delal for showing off with his gifts and rubbing his promotion in their faces, as if they can’t afford to better themselves in turn.

Next thing the tenants are competing to make their own improvements to the building. One barters a stack of gold bracelets and commissions a decorator to whitewash the walls of the stairwell. Another pawns her sewing machine and hires an exterminator. And another sells some silver pudding bowls to have the shutters painted yellow.

With workers occupying the building, hammering and crowding and shouting and spitting, Boori Ma takes to going on afternoon walks and to spending little bits of her lifesavings – rolled up in a cloth and safety-pinned to the free end of her sari – on occasional sweet treats.

One afternoon she is robbed and hurries back to the tenement building searching for comfort. But the tenants are waiting in a huddle to scold her, because in her absence the basin on the stairwell has been stolen and where it once sat there is now a gaping hole spilling torn tubing and bent pipes and looking like a wound. They turf Boori Ma out on her ear with barely a flicker of regret, agreeing that what a smartened up building such as theirs needs is a real durwan.

This story sparked a lively discussion among the group about the politics of poverty  – since we all agreed that poverty and not class or caste lay at the heart of the matter. When you live on the margins, said Melanie, life is precarious: when one thing goes wrong, everything goes wrong.

Ayuba, who is Nigerian, wasn’t holding back either. ‘Just because you are poor doesn’t mean you rally round one another in times of trouble’, he said. ‘We tend to glamorize poverty in the west, but poverty is de-sensitizing and its victims can behave ruthlessly.’

For Amanda, the chief point of interest were the massive social claims that arrived with the basin. All generosity, she argued, establishes fine grades of hierarchy. ‘When the Delals acquired their basin they were effectively saying ‘we’re better than you!’’

The story’s genius lies in exposing how fragile is the perception of equality among the tenants, who, it turns out, are only really ‘the same’ when they unite together against Boori Ma. The rest of the time they are jockeying to obtain an edge over one another. The building improvements they effect are for the greater glory of the giver and not the greater benefit of the community. Their gift-giving is vanity just as their scape-goating is cowardice.

‘It wasn’t all that different in England fifty years ago’ said Melanie, recalling the oft omitted verses from All Things Bright and Beautiful that refer to ‘the rich man at his castle, the poor man at the gate, God made them high or lowly, and ordered their estate.’

Various noises were made about how very rigid social structures can be freeing, because you know your sphere of operation and you know when you’re transgressing. But I’m not sure I buy that line. It’s a bit like Muslim women saying that wearing the veil is liberating. The terms that define both freedoms are far too narrowly delineated for the freedom in question to sprout genuine wings.

More importantly, while it’s easy to judge the characters in Lahiri’s story harshly, we should think twice before doing so. If you’re not one of the poor empathy can only take you so far. It’s a matter of not mistaking what poor people need for what we think they need.

As Amanda pointed out, the world of the poor has its own rules. Life is a struggle. Surfeit, a distant, holy grail of a goal. What’s more the kind of surplus that is represented by an extra basin, for example, is an unknown quantity.

No wonder generosity is so explosive.