Marriage tax allowance

Although it's unlikely your application would be accepted if you weren't eligible, you still won't be fined. If you were accepted, any underpaid tax would be collected through a PAYE code adjustment.

Yes. Widows and widowers are able to claim backdated marriage tax allowance – though only as far back as 2019.

So if you and your spouse qualified for marriage tax allowance at any point since April 2019 but you didn't make your claim before your partner's death, you can apply retrospectively.

You'll get the payment for each year in which both of you were alive and met the qualifying criteria – even if your partner died on day one of the tax year, you'd get the payout for the whole tax year. It doesn't matter if the taxpayer or the non-taxpayer has died, you'll qualify regardless.

Applications need to be made over the phone via HMRC's income tax helpline, where an adviser will take you through the process. 

Please note that if the deceased was the taxpayer, then the surviving partner can apply directly to HMRC. But if the deceased was the non-taxpayer, then the person responsible for managing their tax affairs will have to apply (this may or may not be the surviving partner). Who bears responsibility for managing a non-taxpayer's tax affairs depends on whether the deceased left a will:

• Where there is a will. An executor will be named. This person will need to contact HMRC.
  
  
• Where there isn't a will. An administrator – normally the closest living relative – will need to contact HMRC instead. See the Gov.uk website for more information on establishing who the closest living relative is.