If your pension is increased because of underpin protection, the increase is excluded for annual allowance purposes. You may still have a tax charge, but it’s based on your pension excluding the underpin addition.
It is possible that a few members may have retired before 1 October 2023 under the old underpin rules, had an underpin increase and an annual allowance tax charge in the year they retired. If you are in this group you may have paid too much tax, or asked NILGOSC to pay too much tax on your behalf. HMRC has processes in place to deal with these overpayments and NILGOSC will contact you if this applies to you.
In addition, a few members may have taken their pension before 1 October 2023 and paid a lifetime allowance tax charge and are now due an increase to their pension because of the new underpin rules from 1 October 2023. You will not pay another lifetime allowance tax charge because of this increase and the lifetime allowance is expected to be abolished from April 2024.