Rich mum, poor mum

Anthropologists living among alien tribes will probably all have had their Heart of Darkness moments, when they wonder, appalled, if they can continue with their experiment. For some it will be witnessing female circumcision; for others, cannibalism.

For Wednesday Martin, the fieldworker living among the super-rich of London and New York - the most bizarre and extreme group of mothers in the world - it was the hiring of disabled Disney World guides.

"What did you say?" Martin asked her source, an extravagantly wealthy mother on Manhattan's Upper East Side, when she first heard the latter whisper of them. The idea of paying disabled people to pretend to be part of your family so you can jump queues at theme parks didn't seem credible; it seemed too much of an abuse of wealth and decency. "This so distilled everything specific and often off-putting about this world, I was going to call my book 'Black-Market Disabled Disney Guides'."

Instead, Martin's yet-to-be-published book is called Primates of Park Avenue. It is an anthropological examination of the "rules, rituals, uniforms and migration patterns" of the super-rich mothers of London and New York, and it is surprising in two contradictory ways.

First, the ridiculous extremes we assume are apocryphal turn out to be true. Martin talks to me on the phone from The Hamptons, where the alpha species of Manhattan migrates in summer. I laugh at what she says, then, a second later, I have to check: "They don't actually do that, do they?" Despite being lauded in the media, this group's behaviour in private would mark them out as criminal or insane if they lived among us. Martin leaked the story of the scam used to get into Disney World earlier this summer and it was confirmed in an undercover TV investigation. A scandal ensued and Disney had to tighten its rules.

Second, the reality of these women's lives is the opposite of their media image. They are frenetic and worried, not idle and self-satisfied. They are so busy preserving their status that they can't enjoy it.

"The lives of these rich women I observed, whether on the Upper East Side or Notting Hill, are always portrayed as indolent. Instead I found women who are incredibly busy, with remarkably high levels of anxiety."