I'm very unhappy in my current job and have been considering leaving to freelance. I have an interview next week, however, for another permanent role, which I would happily accept if it were to be offered to me. I have been wondering if there would be any implications if I were to resign from my current job now, and then be offered the other job in a few weeks. I assume that HR at the new company would call my current employer to verify my employment (before making an offer); would my current employer have to mention that I have resigned? If so, would this be a red flag? The person who would be line managing me in the new role is a former client of mine, and I know that he wouldn't mind (and would probably be pleased, as it would mean that I could start sooner than my 3-month notice period would otherwise allow) - I'm just a bit concerned about how it would look to HR.
I know that I could avoid all of this by just waiting to resign my current role until I know if I have the new job or not, but as I plan to leave regardless, I would prefer to get out sooner rather than later.