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 Minister for the Civil Service. Lord Diplock said the following: Lord Roskill said the following. The courts have traditionally been unwilling to subject prerogative powers to judicial review. Judges were only willing to state whether powers existed or not, not whether they had been used appropriately. They therefore applied only the first of the Wednesbury tests; whether the use was illegal. Constitutional scholars such as William Blackstone would have considered this appropriate. The GCHQ case, therefore, was highly important; it held that the application of judicial review would be dependent on the nature of the government's powers, not their source.