About 6 weeks ago I met up with an old friend, we went out for drinks and ended up kissing at the end of the night. We've emailed since but not met in person, and neither of us has mentioned what happened. I can't stop thinking about it though. Is it better to stay quiet or risk the friendship and hope for more?

Maybe the kiss meant nothing, but why don't you ask him out again. What do you have to lose?

I've suggested a few events since but we've been so busy our schedules have completely conflicted. Which in itself may be an answer. I'm very afraid of losing my friend, which is why I've not said anything, they're very very dear to me.

Why don't you ask him about the kiss. Maybe he is conflicted too.

If I'm honest, I'm afraid of what might be said. I don't have a very high opinion of myself, and if he said it meant nothing, I'd be heartbroken. Even if it meant we were never going to date I'd rather think for that moment he liked me. That's why I keep hoping he'll say something, but as time passes, that seems less and less likely. So, I do wonder if I keep quiete, then I won't loose hime as my friend, which, if this is a temporary infatuation,(I'm not sure if it is or not) I would hate to do. I know, not exactly decisive...

Maybe you should back off from texting him, see if he contacts you, at least maybe you will know if he is interested in the friendship.
It could be the kiss confused him too and he does not know what to do either,
I hope things work out positively for you.