I'm gunna throw my nickel in, with a slightly different answer:
The rider was Paul Revere - But - most probably the shouted phrase was "The Regulars are coming!"
I've heard some speculation (which makes some good sense) that "The British" are coming was a later phrase invented or supposed by the first chroniclers of Revolutionary War history.
"The British are coming" ... well, let's put it this way - rather than cause alarm, it might cause ye farmer domiciled at yon Middlesex farm to shake the wife awake and ask sleepily: "Mary, what is that fool yelling about?? Who'd bloody come to tea at this hour??!! I'm going back to bed!"
Whereas the phrase "The Regulars are coming!" would have instantly told yon slumbering Middlesex farmer that something far more serious than a "Johnny come to midnight tea" was in the works.
Speculation? Sure it is...but how many colonists regarded themselves as "American" before the Declaration??
King George's troops were commonly known as "regulars" ...