A person is taxable on the “full amount of the state pension, benefit or allowance accruing in that year irrespective of when any amount is actually paid.
Most state pensions are paid four weekly. This results in 13 four-weekly payments in a tax year, or 14 if a pension’s payday falls on 6 April. Similar considerations apply for weekly or fortnightly payments.
State pensions increase on the day after the weekly payment day in the first full week of the tax year, not on the first day of the tax year.
So how does one determine the amount accruing in the tax year?
HMRC’s guidance, How to fill in your tax return at page TRG6 at Box 8 State Pension says: “Use the letter ‘About the general increase in benefits’ that the Pension Service sent you to find your weekly State Pension amount. Add up the amount you were entitled to receive from 6 April 2021 to 5 April 2022 and put the total in box 8…. If your State Pension changed during the year or you only received it for part of the year, multiply each amount by the number of weeks that you were entitled to receive it….”.