We're reminded of a similar viral thread that did the rounds back in the noughties (originally credited to John Cleese), in which a parody 'Queen Elizabeth II' pens a letter to the US warning them that she will be revoking their independence.
In light of your immediate failure to financially manage yourselves and also in recent years your tendency to elect incompetent Presidents of the USA and therefore not able to govern yourselves, we hereby give notice of the revocation of your independence, effective immediately. (You should look up 'revocation' in the Oxford English Dictionary.)
Her Sovereign Majesty Queen Elizabeth II will resume monarchical duties over all states, commonwealths, and territories (except Kansas , which she does not fancy).
Congress and the Senate will be disbanded. A questionnaire may be circulated sometime next year to determine whether any of you noticed.
"To aid in the transition to a British Crown dependency, the following rules are introduced with immediate effect":
The letter 'U' will be reinstated in words such as 'colour,' 'favour,' 'labour' and 'neighbour.' [...] Generally, you will be expected to raise your vocabulary to acceptable levels. (look up 'vocabulary') [...] There is no such thing as U.S. English. We will let Microsoft know n your behalf. The Microsoft spell-checker will be adjusted to take into account the reinstated letter 'u'' and the elimination of '-ize.'
The cold, tasteless stuff you insist on calling beer is not actually beer at all. Henceforth, only proper British Bitter will be referred to as beer, and European brews of known and accepted provenance will be referred to as Lager. New Zealand beer is also acceptable, as New Zealand is pound for pound the greatest sporting nation on earth and it can only be due to the beer. They are also part of the British Commonwealth - see what it did for them.
Further, you will stop playing baseball. It is not reasonable to host an event called the World Series for a game which is not played outside of America . Since only 2.1% of you are aware there is a world beyond your borders, your error is understandable. You will learn cricket.
You must tell us who killed JFK. It's been driving us mad.
An internal revenue agent (i.e. tax collector) from Her Majesty's Government will be with you shortly to ensure the acquisition of all monies due (backdated to 1776).
Daily Tea Time begins promptly at 4 p.m. with proper cups, with saucers, and never mugs, with high quality biscuits (cookies) and cakes; plus strawberries (with cream) when in season.
God Save the Queen!
*Frantically Googles whether US independence can be rescinded, by order of Queen Elizabeth II (and all of us)*.