DJ Taylor: There's a drawback to spirit guide Bella Moriarty's technique ... she's never particularly exact

It was as a small child, playing innocently in the back-garden of her grandmother's house at Llandrindod Wells, that Bella Moriarty first caught sight of the Devil. What happened next is not entirely clear.

Neither are precise details of the apparition's get-up and demeanour. Bella will only say that there was a general impression of terrible, icy clarity, a fixed and malevolent eye gazing down on her, a suspicion that the world she knew had been tugged from its moorings and sent off in an entirely different direction.

But, however vague the circumstances – and Bella, as she will remind you, was only six at the time – it makes an excellent story, and has undoubtedly contributed to her professional success.

The time to consult Bella is on a Sunday afternoon in north-west Surrey. Dorking, Guildford and Reigate are the locales that know her best – mock-Tudor pubs, usually, in which "psychic sessions" have become such a feature of the cultural landscape that half-a-dozen female conduits to the spirit world can be found plying their trade to an excited and, again, mostly female audience.

Expert observers maintain that it is not simply her early encounter with Lucifer that gives Bella a popularity that some of her colleagues struggle to emulate. There is also the question of her appearance. Most of the mediums are cheerful, middle-aged ladies in flowing robes knocked up out of old curtains; Bella is still in her mid-thirties, has her black hair cut very short and looks like Siouxsie Sioux's younger sister.

Then there is her technique. Rather than being confidential, or chatty, Bella is given to stricken and well-nigh catatonic silences from which she occasionally emerges with an appearance of not quite knowing where she is. This, too, goes down well with the cognoscenti. If there is a drawback to these performances, it is that the advice that accompanies them is never particularly exact.

Bella is prone, for example, to telling her clients that they either have been or may in the future be ill, that they have elderly relatives who have died, or that their lives are not all they might be. Yet, these bromides are usually received with great interest, not least because, as her clients sometimes remark on the way out, she has clearly "been through a great deal". In her defence, it cannot be said that she has yet done any positive harm.