Dear Naamplaw and 2006,
Thank you for your answer

. I am sorry that my question was not clear enough and then led the debate here, I apologized for that
What I meaned is that I want to say I have never do something before (from the past till now) and I may do or not do it in the future. For example;
Q) Have you ever travelled to London?
A)
'I have never travelled to London before'
I may or may not travel to London in the future but I just want to give information (at that time someone asks) that I never travelled to London before.