This was a story in the Mail on Sunday yesterday. Apparently the term 'partner' is now used in place of 'husband', 'wife' or 'spouse' on some HMRC forms. This is attributed by the paper to a socialist conspiracy to destroy marriage.
Well, actually it's used in the question 'Do you have a partner?' instead of something like 'Do you have a spouse, partner (defined as a person you are living with as if you are married) or civil partner?'. So this very probably points to a civil servant trying to save space and write in plain English. Do they really think the Prime Minister and his cabinet discuss the wording on a form?
The article also notes that on the Child Benefit form you are asked to select your title from 'Mrs, Miss, Ms, Mr', and attributes this sequence to a 'nod to feminism'. Well, no, actually. The legislation requires Child Benefit to be paid to the mother, unless the child is living with the father or other person. And most mothers are married women ('Mrs'), followed statistically by unmarried women ('Miss'). 'Mr' comes last because it is the least likely response to the question.