If you had income or capital gains for the year ended 5 April 2016 which HM Revenue & Customs don’t know about, then you must tell them by the deadline of 5 October 2016 so they can send you a tax return to complete. There is no need to tell them about employment income if you have a form P60.

If you miss this deadline, then it would be best to see an accountant. If you already have an accountant, then you will be asked what income you had, and no other action is required.