DURING his two periods as SNP leader, from 1990 to 2000 and from 2004 to 2014, Alex Salmond transformed Scottish and, thereby, British politics. In doing so, he helped ensure that Britain’s character as a multinational state could no longer be ignored.

What led to this transformation? Salmond was a forceful and charismatic speaker. He could read his audiences — whether trade unionists or bankers. But it was his politics that were key. They transformed the SNP.

In the 1930s, the SNP had been a right-wing, and sometimes very right-wing, party representing a mixture of romantics, eccentric aristocrats and minority elements within what used to be called the petty bourgeoisie — but it was squeezed to virtual non-existence between a dominant Unionist Party, that harvested a significant Orange vote, and a challenging and relatively radical Labour Party.

Post-war, the SNP moved towards the centre — sometimes even managing to capture working-class parliamentary seats such as Hamilton in 1967. But it never managed to secure more than a couple. Its main base remained among the “Tartan Tories” of the prosperous farming counties of Scotland’s north-east.

The late 1960s saw two developments which would be of transforming importance. One was the discovery of oil. The other was a surge of working-class mobilisation across Britain as a whole — first against Labour’s anti-trade union laws in 1968-69 and then against Ted Heath’s rehash of them in 1970-71. In Scotland, this radicalisation was deepened still further by the Conservative Party’s failed attempts at shipyard closures on Clydeside and widening protests against the country’s deindustrialisation.

At this stage, it was the left, led by Mick McGahey and the politically radical unions within the Scottish Trades Union Congress, that demanded a parliament for Scotland, a “workers’ parliament,” as it was put by its general secretary at Scotland’s first national assembly in 1972.

Then came oil. As part of Labour’s radicalisation, led by Tony Benn, plans were made for widespread public ownership. This was to include oil — along with stringent depletion controls on the Norwegian model. However, the US said No. In terms of property rights, it was their oil. It was US firms that provided the money and deep-sea technology and did so with a purpose: to break the Organisation of the Petroleum Exporting Countries cartel in the Middle East. They wanted the oil immediately.

The SNP, under its then leader Willie Wolfe, moved quickly to throw in the slogan “It’s Scotland’s oil.” At this stage, some of the Edinburgh bankers came on board. They did so along with leading commercial figures like Sir Hugh Fraser, owner of Frasers stores and the Glasgow Herald, and Roy Thomson of the Scotsman. In the first 1974 election, the SNP secured 11 seats. In the second 17.

Under Wolfe, the SNP now emerged as a successful middle-of-the-road populist party. But it was one which, over the following five years, ultimately opposed Labour’s referendum for a home rule parliament and, in 1979, voted with Tories to bring down the Labour government. In the resulting election, which saw Thatcher become prime minister, the SNP was reduced to two MPs. It never advanced beyond that till 1990.

It was, however, at this point, in 1979, that Salmond, aged 25, began the transformation of the SNP. He had already made his mark in student politics at St Andrew’s. He emerged as one of the leaders of a pool of young leftwingers, the 79 Group, which also included the more experienced former Labour MP Jim Sillars, who had previously led the short-lived Scottish Labour Party.

Together, the 79 Group challenged the centrist policies of the SNP under Gordon Wilson from the left and did so in order to capture the new radical spirit unleashed by the working-class mobilisation of the ’70s, a spirit that continued in Scotland for the following two decades and virtually eliminated the Tories.

Almost immediately, Salmond, along with Margo MacDonald and Stephen Maxwell, were expelled. Though soon readmitted, they remained a minority as they sought to build links with the trade union movement and develop relations with those, like Bill Speirs, future general secretary of the STUC, who wanted to take forward the 1979 home rule legislation on a more radical basis.

It was in this period, largely in response to Sillars and Salmond, that the SNP moved towards what appeared to be a more directly social democratic orientation under the new slogan “Scotland in the EU.” Opposition to Trident also became more central.

These were the policies which Salmond was able to expound when he became leader in 1990 and when, from 1992, the Labour Party began its long march to the right. By 1997, Salmond had increased the SNP vote share to 22 per cent and doubled the number of its MPs.

The enthusiasm around the re-established Scottish Parliament was soon whittled away by the cautious free-market policies of the Lib-Lab coalition. By 2010, as Blairism imploded, the SNP secured 39.5 per cent of the vote for Westminster. By 2011, it had an absolute majority in Holyrood, setting Scotland on its march towards an independence referendum. Defeat in 2014 was followed by Salmond’s resignation. Yet the 2015 election saw the SNP secure 50 per cent of the Scottish vote and 56 Westminster MPs.

This was a measure of Salmond’s achievement — yet an achievement qualified by contradictions that were already apparent. In 2012, opposition to Trident was qualified by support for Nato, a nuclear-armed, first-strike alliance.

“Independence in the EU” might have appeared to give assurance of internationalism and social democratic values under Jacques Delors in the 1980s. Yet by 2010, the EU represented institutionalised neoliberalism — savaging small countries like Greece and Ireland.

In government, the SNP appeared unable to escape the embrace of business lobbyists — with almost every initiative tangled in a web of self-serving consultancy: transport, housing, social care, power and generation. Salmond cannot be blamed for all of this and he certainly can be credited with opposing the US over the bombing of Serbia and the invasions of Afghanistan and Iraq.

His central achievement was different, but also has to be qualified. It was to raise the issue of Britain as a multinational state. This challenge still faces the British labour movement. Salmond answered it in absolutist terms — a separate Scotland — not in class terms.

In the same way that he did not see, or appear to see, the corporate capture of the SNP in office, he did not see how the same forces, national and international, would tie down an “independent” Scotland — or that working-class political advance in Scotland, or elsewhere, has historically depended on united class mobilisation across the nations of Britain.

This is the challenge that still has to be met: how to find forms of class mobilisation that unite the national contingents of working people across Britain — contingents now much more diverse than they were 50 years ago when Salmond began his political career.