OK so I've never done this before as I've been in my company a long time.
I have received a job offer with a fixed start date, further away than the end of my notice period. It's about a month further away.
Do I wait to hand in my notice or do I let my employer know now?
Note that I am the only person who does my role in the company so it may be beneficial to give them an additional month. I am concerned that they may say thanks and let me go after the end of my notice period and I would be without a job for a month.