HMRC are reminding people that there is a limited married or civil partnership tax allowance. A quick summary can be found on HMRC’s part of the Gov.UK website where they say :-
“Marriage Allowance lets you transfer £1,100 of your personal allowance to your husband, wife or civil partner – if they earn more than you.
This reduces their tax by up to £220 in the tax year (6 April to 5 April the next year).
To benefit as a couple, you (as the lower earner) must have an income of £11,000 or less.”
Tax Barrister, Accountant