One space or two...?

I discovered something on twitter the other day that shook my entire world.

It turns out that I have been typing incorrectly for my entire life. After a full stop I always hit the space bar twice. That's the way I was taught was correct, that's how I've always done it. A double tap on the space bar at the end of a sentence is like breathing to me. But apparently one space is actually correct and therefore, as a writer by trade and by leisure, I must re-wire my brain and force my fingers to conform.

I think I'm more amazed that in all my years in education, at 6th Form and university, no-one has ever pulled me up on this astounding error, which I consider to be such a vital part of the writing process.

On the bright side, at least I found out now and not 30 years down the line...