Barnett served as Chief Secretary to the Treasury from 1974 to 1979, gaining a seat in the cabinet from 1977 onwards, and was Denis Healey's right-hand man in the Callaghan Government. During this time he oversaw the devising of what is known as the Barnett Formula by which public spending is apportioned between England, Scotland, Wales, and Northern Ireland. He subsequently joked about the strange and unexpected form of immortality that was accorded to him by "having his own formula". Following the Scotland Act 1998 and devolution, he argued that the Formula was unfair to England and should be abandoned or revised. He reiterated this view in 2014 shortly before the Scottish independence referendum, calling the Formula unsustainable and saying it had become an embarrassment.