One of the persistent mysteries of royal reporting is why anyone, anywhere, would believe anything that 'old school chum' Jessica Hay says about Kate Middleton.

Hay gives frequent interviews to an Australian magazine named New Idea, in which she makes random claims, the latest of which is that her mother Carole Middleton is going to act as nanny for the royal baby when it arrives in the summer.

Hay is the source of a variety of fake Kate stories, most notably she is the ‘best pal’ who claimed that Kate had posters of William on her bedroom wall at boarding school – a story categorically denied by Kate on air in her engagement interview - and Hay was also behind a bizarre story, subsequently withdrawn, that Kate had faeces smeared on her bedsheets at boardign school as part of a bullying campaign.

Miss Hay’s story lacked credibility, to say the least, as Kate was not a boarder at the school in question.

Royal sources previously said of Miss Hay: "She is not and never has been a friend. Many claims are just fantasies."

One can understand why the Aussie gossip mags may not be too troubled at repeating Hay's nonsensical claims. But is the Royalist being naive to wonder why on earth the supposedly more reputable LA Times - which is today running the 'Carole nanny' story - would do the same thing?