 The emergence of Plaid Cymru (and the Scottish National Party) prompted the Wilson Government to establish the Kilbrandon Commission, leading in turn to Welsh Labour to once more consider the case for devolution - this time coming out in favour.Victory in the February 1974 General Election pushed devolution onto the political agenda, culminating in the decisive vote against a Welsh Assembly in the 1979 referendum.The Nationalist threat to the party's industrial heartland fell away in the 1970s.