“And what was this payment for?” A steady finger points to a figure in euros on a bank statement.
“Fish food… A big tub of fish food.”
“No, no… it was a big fish – a sea captain I know – he lands his boat in Kent, it was a fish this big,” (hands spread in a widening gesture). “We ate it for tea one day.”

The enquirer is my husband, financial documents in hand, in a scene reminiscent of an Agatha Christie dénouement, set in a wood-panelled drawing-room with all the potential culprits present. The first respondent, flustered and erratic, has been a friend and neighbour of our elderly relative for 30 years; the second respondent, with an air of cool bravado, is the French live-in carer; and the silent party is our elderly relative herself. But there are no fish to feed – no aquarium, no fishpond – and, it turns out, our relative has no recollection of a Kentish fish supper.

Thus begins an eye-opening couple of weeks during which we discover, piece by piece, how our elderly relative – let’s call her Clara – has been defrauded. Over the past four months, the carer has stolen upwards of £10,000 from her through internet banking and online purchases (including not fish, but oysters and mussels delivered direct to her Parisian family). The neighbour not only holds all Clara’s papers (including bank statements sent directly to her), but has also been contacting the solicitor weekly to seek a change in power of attorney and other matters regarding Clara’s will.

What of the negligent solicitors, the unscrupulous builders and house clearers?

In addition, she has arranged for her own financial advisor and friend (they’re both shining stars in the ballroom-dancing firmament) to meet Clara as a potential client (the neighbour, of course, in line to receive an introductory commission).

Fortunately, Clara is someone who, as she says herself, likes to have all the information before she makes a decision; in other words, she rarely makes a decisive change. Despite the neighbour’s persistent campaign, we discover no legal or administrative matters have been altered, and following a few fraught days, all is largely resolved. The carer is summarily banished and the neighbour persuaded against further action, though this is more tricky, since Clara won’t hear a bad word against her.

As for the stolen money, since she’s now approaching 92, Clara doesn’t wish to pursue it, and who can blame her. She is now happily settled in her retirement apartment with her cat and her new, trustworthy, live-in carer, reading two newspapers daily, always up for a political discussion, often with a ready smile. But the money is gone and, in all likelihood, a real operator remains free to prey on her next vulnerable victim.

Should we have seen this coming? Well, Clara’s situation with the “helpful” neighbour and the carer seemed to be working, though perhaps it was convenient for us to believe that all was fine. It could be argued that the neighbour didn’t trust us – that till then we’d shown so little interest in our relative’s affairs she wanted to seize control with the best interests of her friend at heart (though this does rather ignore the fish-food collusion with the thieving carer).

With hindsight it’s impossible not to wonder whether we should we have intervened earlier, despite the fact Clara is an individual of sound mind and firmly held opinions, who had not asked us for help.

What we failed to take into account is that Clara is a dedicated bridge player, and the whole point of a bridge player, we recently discovered, is that they don’t tell you what’s really going on. We had simply trusted that she would let us know when she needed help. This is not the same sense of the word as Clara trusting that her neighbour would act in her best interests and that her carer, who appeared attentive and kind, would not steal from her. It is not the same at all; this is, perhaps, our excuse.

You could put it all down to straightforward misfortune – Clara’s entanglement with two individuals at a particular moment in her life: one, an overzealous friend, spying an opportunity, the other, a criminal operating as a carer. Yet, only a few months earlier, we’d found ourselves in a similar situation with another distant relation – let’s call her Rowena – which to my mind was a more alarming sequence of events, since it was officially sanctioned.

Rowena lived in a highly desirable flat in Notting Hill: a corner desk with a window shaded by a fig tree in the back yard, a kitchen with stepladder cupboards, and an airy front room overlooking the most famous private communal garden in London, for which she had a key. She was an architectural historian and her flat was full of her papers, her letters to and from Anthony Blunt, her seventeenth-century chairs, drawings and paintings, her designer clothes, her collection of Chanel handbags, her will, and some photographs, like fashion plates, of her youthful self.

When Rowena could no longer cope, she was moved into a care home, and, because she had no close relatives, her affairs were taken over by a deputy acting for the official solicitor. It gradually became clear to her cousin, my husband’s father, that all was not as it should be – bills were not being paid, letters from the local authority remained unanswered – and so he asked if we might be able to help.

There are too many instances to record here of the deputy solicitor’s neglect – his lack of contact with the local authority which led to the threat of bailiffs, his handling of the sale of Rowena’s Herefordshire bolthole, his persistent letters quibbling over details of the care home’s perfectly normal contract (letters which he could, of course, charge to her estate), and his utter refusal to meet my husband, who had, by this stage, applied to take over the management of her affairs. But the worst was yet to come.

A month before he relinquished control, the deputy solicitor engaged a builder to refit the Notting Hill flat for £150,000, despite the fact that agents had all advised selling the flat without redecoration. We arrived there one spring morning to find the locks had been changed. After speaking to neighbours and peering through the window, it soon became apparent, to our utter dismay, that the flat had been cleared. None of her belongings remained. When challenged, the deputy quoted the builder as saying there was “nothing of value” there. (There was, however, a ringing endorsement on the builder’s website by said deputy.) So, either Rowena’s possessions, the papers she was intending to leave to her university, her valuable pieces, her personal history, were all on a skip, or, once again, it was a question of theft. When we complained to the deputy’s ombudsman, they were of the opinion he had done nothing wrong.

While this particular instance is both concerning and distressing (we never did reveal the loss to my father-in-law), it feels like the tip of an iceberg: what happens to the thousands of care home residents who do not have relatives looking out for their interests? And if our experience is anything to go by, what of the negligent solicitors, the unscrupulous builders and house clearers? Who is regulating what appears to be a highly lucrative racket? If an official deputy solicitor is part of it, if the ombudsman looks away, who can we trust?

Siân Wainwright is an Oxford-based rare book dealer and occasional musician, and has had a novel in the wings for longer than she cares to admit to