What do the words “so”, “and”, “but” and “or” have in common? They’re all conjunctions, meaning they’re used to connect parts of a sentence together, and they’re all words you’ve probably been told at some time that you shouldn’t start a sentence with.
A cursory glance around the web, however, quickly shows this to be stylistic preference rather than a hard and fast rule. Take a look at this soccer match report on BBC Sport, where there are paragraphs beginning with “and” and “but”. It’s hardly an isolated example.
Really, there’s not a lot wrong with doing it, as long as it’s done well and in a grammatically correct way. If done badly, it can result in fragments – sentences that don’t make sense on their own as they refer back to the sentences before them. Examples of this could be:
“We missed the train. So we went to the pub until the next one came.”
“I thought I heard a knock at the door. But there was nobody there.”
Poor writing like this is the reason why some editors and grammarians discourage starting a sentence with a conjunction, and while we don’t want to stifle snappy and inventive writing, we also tend to pass on this advice to writers in the interests of concision and consistency.