In 1968, Edward Heath issued his 'Perth declaration', in support of a Scottish assembly, in the wake of growing nationalism. However, the cause went unanswered during his turbulent premiership, and under Margaret Thatcher and John Major's leadership, the Conservatives vehemently opposed devolution, and campaigned against it in the 1997 devolution referendum. Following the Scottish Parliament's establishment in 1999, they have vowed to support its continued existence, and along with Labour and the Liberal Democrats, they supported the Scotland Bill (2011), granting further devolution of power. They campaigned alongside Labour and the Liberal Democrats against full Scottish Independence in the 2014 Scottish Independence referendum.