Good question

Though, I must admit, the answer is perfunctory.

Lord Stoddart of Swindon (a favourite personality on this blog) asked HMG

whether the policy advocated by the Prime Minister in his speech on 25 June that recipients of welfare benefits should be described as claimants and not customers will be applied to the National Health Service and HM Revenue and Customs, and users described as patients and taxpayers respectively.

Words matter, you see.