Three million UK couples have claimed their Marriage Allowance. However, it is estimated that a further one million have not.

The Marriage Allowance allows married couples or those in a civil partnership, where neither pay beyond the basic tax rate, to transfer 10% of their unused personal allowance to their spouse or civil partner. This, in turn, can reduce their tax bill by up to £238 a year in 2018/19. The allowance was introduced in April 2015, and appropriate claims can be back-dated to prior years.