Hello, my name is ***** ***** it is my pleasure to assist you with your question today.
How long have you worked there for?
you are free to hand in your notice at any time. The employer cannot refuse to accept your resignation, even if that is what they say. You would be expected to submit the notice period which is in your contract and if no contract or notice period exists then you would only be expected to give a week's notice of leaving. If you are signed off sick then you can remain on sick leave during your notice period and once the notice period expires your employment would automatically terminate
Hope this clarifies your position? If you could please let me know that would be great, thank you