The Duchess of Cambridge’s diamond and pearl earrings were among the most admired at St Paul’s Cathedral over the Bank Holiday.

So it will come as a surprise to those who spent a fortune on jewellery at Graff and Asprey that Kate’s sparklers weren’t diamonds at all and cost a mere £48 ($75).

In fact, they were a very good copy under the description “fabulous fakes” designed by Belinda Hadden, ex-wife of top PR man Abel Hadden.

Belinda Hadden was astonished to learn that Kate had worn her creations on the balcony of Buckingham Palace.

Mother-of-three Belinda Hadden, who set up little-known Heavenly Necklaces in the Nineties as a hobby when her daughters were small, said: “I was at a wedding, so I had no idea Kate had worn my earrings until another client sent me an email asking: <<Are they the same as mine?>>”

The Duchess of Cambridge’s diamond and pearl earrings were among the most admired at St Paul’s Cathedral over the Bank Holiday

It wasn’t long, however, before the “Kate effect” began to work, with internet chatrooms abuzz.

Belinda Hadden, daughter of the late Tory MP for Gosport and Fareham, Hants, Sir Reginald Bennett, says: “Within the next 24 hours, I had sold out. I sold 60 on my website, which is the amount I would usually sell in a whole year.”

Belinda Hadden, who sources her fakes from India, China and Hatton Garden in London, says: “They are made of finest grade cubic zirconia, but what makes them look authentic is the settings they are in.”

The pearls, she says, are made from ground-up freshwater pearls reconstituted with resin.

She adds: “Usually, I would never dream of talking about my clients but, in this case, Kate’s earrings were outed on various blogs.

“I had no idea there was this huge internet chat about where, when and what she wears.”

Belinda Hadden designs 75% of her earrings, necklaces and bracelets herself and explains: “I have always loved jewellery and I did a short design course – two terms – at a further education centre run by my local council.”