Becoming a royal involves making many sacrifices. Privacy, a career and, it turns out, the chance to nonchalantly throw back a freshly-shucked oyster at a mate's wedding.

Oysters, or ostreidae as they are known in curtseying circles, are on a list of foods the royal family is reportedly banned from eating in public.

In fact, all shellfish is banned, according to the list, which was leaked to The Sun newspaper over the weekend.

The reason? Shellfish are more likely to be iffy than other foods and the British Empire can ill afford (geddit?) the Duke or Duchess of Cambridge, or the 91-year-old Queen, missing an event due to an undercooked prawn.