RadarOnline.com can reveal Kate Middleton is said to be "deeply unsettled" by one of the most macabre royal travel rules – a requirement she must carry a full mourning outfit in her luggage every time she leaves the country.

The Princess of Wales, 43, is known for her elegance and composure at public engagements, from playing tennis with Roger Federer to handing out design awards. But behind the glamour lies a centuries-old royal protocol dictating she must always be ready to appear in black should tragedy strike while abroad – a rule dating back to the death of King George VI in 1952. Article continues below advertisement

A Rule Born from Royal Tragedy Tap Here To Add Radar Online as A Trusted Source

A royal insider claimed: "It's an incredibly grim rule, and Kate hates it. The

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