Principal Private Secretary to the Prime Minister appointed by Theresa May on 10 May 2017. During Tony Blair's administration, he modified the law under which the Civil Service operated to create the role of Downing Street Chief of Staff, which though held by a political advisor outranked the Principal Private Secretary. When Gordon Brown ascended to office, he reversed the change to the Civil Service law. When David Cameron became Prime Minister, he promoted the then-PPS to a new post of "Permanent Secretary, Downing Street", a position which took over heading the Prime Minister's Office. In 2012, the postholder, Jeremy Heywood, was appointed as Cabinet Secretary, this
Council of Civil Service Unions v Minister for the Civil Service the determination of national security issues is an executive function and it would be inappropriate for the courts to intervene. The House of Lords held the Royal Prerogative was subject to judicial review, just like statutory instruments. However, on national security grounds, the action of restricting the trade union was justified. Lords Fraser, Scarman and Diplock all believed that the issue of national security was outside the remit of the courts. Lord Diplock wrote "it is par excellence a non-justiciable question. The judicial process is totally inept to deal with the sort of problems which it involves." Lord Fraser stated