I handed my notice in on 2nd October with immediate effect due to health reasons. I'd been on long term sick leave (work related) for a while and for me to give the required 4 weeks notice would only have been me remaining on sick leave for another 4 weeks anyway. Employer has now written to me to say that I have to give 4 weeks notice and therefore my last day with them will be on 30th October even though I've already started a new job! Don't understand this at all!