The government does it. The bible does it. And more importantly The Economist does it. We could spend hours talking about conjunctions, grammatical structure and the power of a little and, so or but at the beginning of a sentence. But we won’t. Instead, we’ll let these guys convince you…
Steven Pinker, cognitive scientist, psychologist and linguist:
“Many children are taught that it is ungrammatical to begin a sentence with a conjunction. That’s because teachers need a simple way to teach them how to break sentences, so they tell them that sentences beginning with “and” and other conjunctions are ungrammatical. Whatever the pedagogical merits may be of feeding children misinformation, it is inappropriate for adults.
There is nothing wrong with beginning a sentence with a conjunction. “And”, “but” and “so” are indispensable in linking individual sentences into a coherent passage, and they may be used to begin a sentence whenever the clauses being connected are too long or complicated to fit comfortably into a single megasentence. The conjunction “because” can also happily sit at the beginning of a sentence. Most commonly it ends up there when it introduces an explanation that has been preposed in front of a main clause, as in: “Because you’re mine, I walk the line.” But it can also kick off a single clause when the clause serves as the answer to a why question: “‘Why can’t I have a pony?’ ‘Because I said so.'”
From 10 Grammar Rules its OK to Break, the Guardian, 2014
Kingsley Amis, novelist, poet, critic, and teacher:
“And the idea that and must not begin a sentence, or even a paragraph, is an empty superstition. The same goes for but. Indeed either word can give unimprovably early warning of the sort of thing that is to follow.”
From The King’s English (1997)