

Half a billion pounds of UK tax relief sits unclaimed every year. The form takes five minutes. HMRC will never chase you. One of you has to be under £12,570. That's it.
Backdated Marriage Allowance (full claim 2026/27)
Total £1,260. Apply free on gov.uk in five minutes - skip the 40% commission middlemen.
Key takeaways
Marriage Allowance lets you transfer £1,257 of your personal allowance to your spouse, saving them up to £252 in tax each year
You qualify if one of you earns under £12,570 and the other is a basic-rate taxpayer
You can backdate the claim up to four tax years, taking the lifetime saving above £1,200
Apply free on GOV.UK in five minutes - no third-party 'reclaim' service needed