Harney & Sons released a limited edition tea blend emulating the besposke Earl Grey tea blend which is known to be Queen Elizabeth II's favorite. It's called Diamond Jubilee of course...
Here, it is a variation of the classic mix with an addition of a richer palette of citruses.
"The tea is a bespoke blend which includes the Queen's favourite, earl grey tea, plus black teas, lemony bergamot and grapefruit essences."
If you want to reproduce the royal experience as best you can, try using Malvern water for brewing your tea. The Queen is said to be an unconditional of the ancient spring carrying cases of its prophylactic water in her luggage whenever she travels.