We're approaching the 40th anniversary of the last time citizens of the UK were asked about Europe.

 

Of course then, on 5 June 1975 to be precise, voters were consulted regarding the European Economic Community (EEC) or Common Market. Should the UK stay in, or should it get out?

It had only been a member for two-and-a-half years, joining along with the Republic of Ireland on 1 January 1973, but Harold Wilson, recently re-elected Prime Minister with a wafer-thin majority, had promised a referendum and thus duly delivered.

Cannily, Mr Wilson gave his divided Labour Party a free vote, while most Conservatives (including their then fledgling leader Margaret Thatcher) campaigned to remain in the EEC; the SNP, meanwhile, wanted out. Mr Wilson hailed his negotiations with Brussels a success and took his case to the country.

The Yes campaign comfortably emerged the victor, with England voting 68.7 to 31.3 per cent in favour, and a less enthusiastic Scotland by 58.4 to 41.6 per cent. Shetland and the Western Isles voted to leave, the only two local authority areas to do so.

One can overdo historical analogies (and I usually do), but the parallels are striking four decades later. Now it is a Conservative Prime Minister in possession of a wafer-thin majority and a party that requires a free vote to mask its divisions. And the SNP is now pro rather than anti.

Indeed so pro that Alex Salmond - now emerging as the leader of the SNP's fundamentalist wing - recently confirmed he would campaign for a Yes vote on Europe shoulder-to-shoulder, hand-in-glove, or my favourite beloved of many an SNP press release, "in cahoots with" Tory Chancellor George Osborne.

"I share platforms with everybody," the former First Minister told his favourite broadcaster the BBC, "except fascists and non-democrats". Inevitably this prompted cries of "hypocrisy", but then Mr Salmond has made a career out of ever-shifting points of unshakable principle, so in a funny sort of way he was being entirely consistent in his inconsistency.

Europe is one of those issues on which the SNP has an apparently simple position (pro) but which, on closer examination, becomes a bit of a mess. Shortly before last year's European Parliament elections Mr Salmond, Nicola Sturgeon et al started inserting little caveats into their pronouncements, largely to the effect that the European Union wasn't perfect, "far from it".

But to my knowledge there's been no attempt to explain in what way they would help make it a more perfect union. Indeed, there's little evidence the SNP has done any serious thinking about the EU since around 1988, when it committed to "independence in Europe", a slogan rather than a policy.

Even that didn't make an awful lot of sense: why so alive to sovereignty within the UK but relatively relaxed when it comes to the EU?

But it goes deeper than that, for the roll call of things the SNP doesn't like about Europe is quite long: the single currency, Common Fisheries Policy and closer fiscal integration, which the present First Minister has several times made clear she doesn't support. Even the European Convention on Human Rights (which exists separately from the EU) has come under fire from Nationalists, chiefly its ruling against a blanket ban on voting rights for prisoners.

Then there's the rhetoric. SNP press releases rail against the "Tory obsession with ripping Scotland and the rest of the UK out of the EU" and Scotland being "dragged out" against its will. Yet when Unionists deployed similar language to describe Scotland vis-à-vis the UK they were accused of being alarmist and melodramatic. Similarly, it's difficult to argue that Scotland leaving a highly-integrated UK would somehow be hassle free but the UK exiting a much looser union would "threaten" jobs and the economy, yet that's exactly the SNP's position.

To guard against being ripped or dragged, meanwhile, the SNP points to its "double majority" safeguard under which every part of the UK would need to approve withdrawal for it to take effect. On one level this is a clever piece of political positioning, but on another it's constitutionally incoherent. Perhaps the UK government should agree with the proviso that the same "double" (actually quadruple) majority apply to any future independence referendum; bamboozle the Nationalists with their own contorted logic.

The SNP also ties itself in knots when it comes to the referendum increasingly likely to be held at some point next year. Yesterday Labour finally bowed to the inevitable and made it clear its MPs would support the necessary legislation, which means virtually the only Members traipsing through the No lobby in the House of Commons will be "the 56", and on the flimsiest possible basis; supporters of self-determination for Scotland but not, it seems, the UK.

Which isn't to say the Prime Minister has covered himself in glory when it comes to matters European. It remains unclear what exactly it is he hopes to get out of his Wilson-style "renegotiation" with Brussels, while he's also set himself up to fail by making freedom of movement a "red line" issue.

That said, Mr Cameron finds himself in a relatively strong position: Ukip is weak (despite having won nearly four million votes) and he has an overall majority, thus the PM's apparently desire to hold a referendum sooner rather than later.

Last week Mr Salmond was full of sage advice derived from his experience of last year's independence ballot, ie don't let unpopular politicians run the show and guard against a dynamic in which it looks like "the establishment", business or otherwise, is dictating how "the people" ought to vote.

Recently Jim Murphy, a more successful Europe Minister than he was Scottish Labour leader, also set out four clear lessons from Scotland: the need to fight like "an incumbent and an insurgent", "passion as well as facts", that businesses must "speak up early" (unlike in Scotland), and a realisation that no matter what the outcome, the forthcoming referendum "will not settle the European debate for a generation".

Yesterday a YouGov poll showed what such surveys usually show in a Scottish context, that 68 per cent of Scots want to stay in the EU and 32 per cent would quite like to go, ie less Eurosceptic than England where the latter figure is usually a few points higher. Moderate opinion, meanwhile, is actually hardening in favour of the status quo, a phenomenon ironically aided by the rise of Ukip in general and Nigel Farage in particular.

Yet as the recent Scottish experience demonstrated, opinion poll-derived complacency can produce close shaves. But despite the hyperbole of tribal politics, the SNP and Conservatives are actually on much the same page on this issue, both want to remain part of a reformed Europe, and in that respect a Scottish Yes campaign led by Nicola Sturgeon can only pile up votes which make that more likely.