If you know me, you're in danger.
If others know me, you're in danger.
Ignorance is bliss, you're safer forgetting me.
As soon as you know me, good luck.
If you know me, you hate me.
It's better that you forget.
As soon as you know, you can't resist.
You need to tell someone what happened, it's the rule.
Ever present, but undetected. I'll never stop. My only weakness is the British Prime Minister, only he can end me.
Who am I?
"I hate you" is not an answer, but you may put it in your comments/answers if you really do.
A better question would be "What am I?"