Thousands of people are being warned they could be missing out on up to £252 each year.
HM Revenue and Customs (HMRC) said more than 2.1m couples currently benefit from Marriage Allowance, but estimates that thousands more eligible couples are not claiming the extra cash.
This is often because they don’t realise they may be eligible, particularly couples where one partner has retired, has given up work to take on caring responsibilities, or is unable to work due to a long-term health condition.
