If the 1960s witnessed the entry of the SNP into the Scottish political mainstream after more than three decades on the fringes, then it was in the early 1970s that the potential threat that the party could pose to the established political and constitutional order became fully apparent. As any account of twentieth-century Scotland will narrate, the advances achieved by the SNP at the two general elections of 1974, when the party had seven and then eleven MPs returned to Westminster and, perhaps more significantly, polled twenty-two and then thirty per cent of the vote, transformed Scottish politics permanently. At the October 1974 contest the SNP overtook the Conservatives to finish in second place in terms of popular support; beyond the eleven constituency victories, the party had finished second in an additional forty-two seats. Scottish developments were granted further significance at Westminster as a result of the precarious parliamentary position faced by the Labour government after October 1974: the government’s majority in the Commons was just three, and would evaporate by 1977, granting the new SNP contingent added weight and influence. And while support for the SNP would ebb in the late 1970s and 1980s, the party would never again return to the irrelevance it had previously endured.

The striking upsurge in support for the SNP evident in the early 1970s can perhaps be explained by the political atmosphere in which the 1974 elections were held. The Royal Commission on the Constitution established by the Labour government in 1968 as a response to the SNP victory at Hamilton, now led by Lord Kilbrandon after the death of the original Chair Lord Crowther, published its final reports in October 1973, with a majority of the Commissioners supporting legislative devolution for Scotland, returning questions of constitutional reform to political prominence. Continued concerns over the state of the Scottish economy, and the initial rejection by the Heath administration of calls for government assistance for struggling industrial concerns, generated further discontent with the UK government among Scottish voters. Important here was the ‘work-in’ at Upper Clyde Shipbuilders (UCS) in 1971–2.