SA1 is a form used in the United Kingdom to notify HM Revenue and Customs (HMRC) that an individual is starting to receive a pension or other form of regular income. The individual or their representative use the form to inform HMRC of their pension income so that HMRC can set up the appropriate tax code for the individual and ensure that the correct amount of tax is being deducted from their income.

The SA1 form can be used for various types of income, including the state pension, private pension, and annuity income. The form must be completed in full and returned to HMRC as soon as possible after the individual starts receiving the income.

If an individual is starting to receive pension income, they should contact their pension provider and ask them for an SA1 form. The form can also be obtained by visiting the HMRC website. If you have any questions about the SA1 form or need help with your tax affairs, you may want to contact HMRC for assistance.