If you are entitled to the marriage allowance and have not yet applied, then you could receive a payment of up to £1,220 from HMRC. The marriage allowance is available to qualifying married couples and those in a civil partnership where a spouse or civil partner is a non-taxpayer i.e., has an income below their personal allowance (currently £12,570).
The allowance works by permitting the lower earning partner to transfer up to £1,260 of their personal tax-free allowance to their spouse or civil partner. The marriage allowance can only be used when the recipient of the transfer (the higher earning partner) doesn’t pay tax at more than the basic 20% rate of Income Tax. This would usually mean that their income is between £12,570 to £50,270 in 2020-21. The limits are different if you live in Scotland.
If you meet the eligibility requirements and have not yet claimed the allowance, then you can backdate your claim to 6 April 2017. This could result in a total tax break of up to £1,220 if you can claim for 2017-18, 2018-19, 2019-20, 2020-21 as well as the current 2021-22 tax year. If you claim now, you can backdate your claim for four years (if eligible) as well as for the current tax year.