Downing Street Chief of Staff
The Downing Street Chief of Staff is the most senior political appointee in the Office of the Prime Minister of the United Kingdom , acting as a senior aide to the Prime Minister , a powerful , non-ministerial position within Her Majesty's Government . 
<triplet> Downing Street Chief of Staff <subj> Prime Minister <obj> appointed by <triplet> United Kingdom <subj> Prime Minister <obj> office held by head of government <subj> Her Majesty's Government <obj> executive body <triplet> Prime Minister <subj> United Kingdom <obj> country <triplet> Her Majesty's Government <subj> United Kingdom <obj> country