R (Alvi) v Secretary of State for the Home Department [2012] UKSC 33, where the Home Secretary sought to argue that she had a residual common law right using prerogative powers to amend the rules applying to immigration controls, in this case those that governed work permits for those in skilled occupations. The Supreme Court, led in this instance by Lord Hope, rejected this argument on the basis that ever since the Immigration Act 1971, matters pertaining to immigration control, previously governed by prerogative power, had been subject to statutory control alone. Any notable change in the relevant rules therefore had to be approved firstly by Parliament.