02/08/2017 6:52 AM AEST | Updated 02/08/2017 6:52 AM AEST

This Is The One Outfit The Royals Must Always Pack (But It's For A Pretty Poignant Reason)

It’s all part of the protocol.

The Royal family are well accustomed to adhering to dress codes and sartorial tradition.

Which is why it comes as no surprise that these stipulations are even extended to their suitcases.

Before leaving the UK, every member of the Royal family must pack a 'black mourning outfit', according to The Sun.

In the unfortunate event that a Royal should pass away while they're travelling, they must return to the country in the traditional garments to show their respect.

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Camilla, Duchess of Cornwall and Catherine, Duchess of Cambridge on a balcony at the Cenotaph in Whitehall, central London for the annual Remembrance Day Service.

And there is good reason for the rule. In 1952, Queen Elizabeth II was on a Royal tour of Kenya with Prince Philip when her father George VI died.

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Queen Elizabeth II is saluted by the crew as she leaves her Viking airplane of the King's Flight, London Airport, June 3rd 1952.

Unprepared, the Queen had to wait on the plane until someone brought her a black outfit before she disembarked - otherwise it would have looked inappropriate and disrespectful.