Female wedding guests are traditionally placed in a quandary; they must look smart enough not to disgrace their family or insult the bride, yet not look so sartorially stupendous that they detract from the bridal dress.

This nicety of etiquette is even more important when attending a royal wedding, a very public event after which the outfits of the guests are endlessly analysed and criticised in every newspaper, from the sensationalist tabloids to the usually stolid and unexcitable broadsheets.

Most of the famously vitriolic fashion commentators of the UK press agreed that one of the fashion successes of the recent British royal wedding was Spain’s Princess of Asturias. Perhaps with her 2004 wedding so fresh in her mind, she was able to empathise with Catherine Middleton’s situation and choose the perfect outfit.

Of course, the Duchess of Cambridge and the Princess of Asturias have far more in common than an interest in designer clothes; both are commoners who have married into European royalty. Prince William of Wales is second in line to the throne, the Prince of Asturias, first and, until his marriage to Letizia Ortiz Rocasolano, Prince Felipe was suffering from the accusations of aimlessness that will be all too familiar to Prince William’s father, the Prince of Wales.

It is generally agreed that under the influence of Letizia, Prince Felipe’s popularity has increased enormously. Not only has she obligingly provided Spain with the Infantas Leonor and Sofia, but this highly intelligent former TV journalist has also improved the survival chances of the Spanish royal family. Naturally the British hope that this latest alliance between Prince William of Wales and Catherine Middleton will mark an equally successful alliance.

Considerably less down to earth than Spain’s royals, the Windsors have had to overcome a great deal of bad press over the past couple of decades, the low point being the accusations of coldness and heartlessness following the death of Diana, Princess of Wales. It was alleged that only the intervention of the Prime Minister persuaded the Queen to return to London from her summer holiday in Balmoral and show some solidarity with her shell-shocked public.

The Middleton clan have also had to endure several years of close scrutiny by the British media, with various embarrassing relatives being exposed. The Princess of Asturias found her youngest sister’s suicide becoming a point of national discussion rather than a family tragedy and as a divorcee, her past was potentially problematic.

It isn’t easy for a commoner to adapt to the often bizarre rituals of life as a royal, but if Princess William of Wales (to give her one of her new titles) is to make a success of her marriage to the second in line to the throne, she could do a lot worse than follow the quiet dignity of Letizia, Princess of Asturias.