If you are a basic rate taxpayer, since 6 April 2016 you have had a £1,000 Personal Savings Allowance (£500 if you are a Higher Rate taxpayer). This means most people no longer pay tax on their savings income. Since 6 April 2016, no tax has been deducted from interest paid on non-ISA savings accounts. Interest from ISAs does not count towards your Personal Savings Allowance because it’s already tax free.
If you have savings income over your Personal Savings Allowance, you are responsible for making sure you are paying the correct tax directly to HM Revenue & Customs.
For further information please visit Gov.uk