The “sumptuous ruby trilogy ring”, according to the study, is surrounded by smaller diamonds.

It was designed by her future husband Anthony Armstrong-Jones to resemble a rosebud, after Margaret’s middle name Rose.

The engagement ring belonging to Grace Kelly also makes the top 10, with 10,560 searches in the past year.

The movie-star turned Princess’s ring, given to her by Prince Rainier of Monaco, was a 10-carat, emerald-cut diamond from Cartier, worth nearly £3million.