by mullet on Sat Dec 10, 2011 4:33 pm
If HMRC send you a return to be completed (or a "notice to file"), then you have to complete/submit regardless of your level of income or whether or not you are liable to tax. But if they don't send you one you don't have to do anything if you do not have a tax liability.
If you do receive tax returns but no longer need to, just ring HMRC and ask to be taken out of self assessment. But you will still need to file a 2010-11 return if already issued to you.