Parliamentary Private Secretary to the Prime Minister Bonar Law's Parliamentary Private Secretary, J.C.C. Davidson acted in effect as his Chief of Staff. Margaret Thatcher's downfall from the Conservative Party leadership in 1990 is attributed by many to the actions of her Parliamentary Private Secretary, Peter Morrison, in failing accurately to count votes amongst Conservative backbenchers. Some Parliamentary Private Secretaries to the Prime Minister go on to hold higher office; Lord Dunglass served as Parliamentary Private Secretary under Neville Chamberlain and later went on to serve as Prime Minister in his own right. There can be multiple Parliamentary Private Secretaries to the Prime Minister at a given time.
Prime Minister of the United Kingdom powerful than the American presidents, as the Prime Minister is part of the legislature, and unlike presidents, can directly initiate legislation. Thus, Dowding argues that adding to these powers, makes the Prime Minister less like presidents, and that what Britain is witnessing is not presidentialisation but, increase in powers overtime, can be best explained as "Prime Ministerialisation" of British politics. Regarding the thesis, Dowding writes: "The presidentialisation of the Prime Minister thesis should be expunged from political science vocabulary, to the extent that the forces identified by those who pursue the thesis exist, they do not make the British Prime