EU referendum: Parallels with 1975
One of the arguments used most frequently in favour of the principle of holding a referendum is the suggestion that a plebiscite on a particular issue will produce some sort of decisive result that settles the matter.
The evident falsity of this idea is easily demonstrated by the last two referendums in mainland Britain - on a proposal to introduce a change in the electoral system in 2011 and on Scottish independence last year. Neither of these issues could possibly be described as having been resolved.
But it is the 1975 referendum on Britain's continued membership of Europe that provides the best example.
Even with a stonking majority of two-to-one (67.2% to 32.8%) in favour of remaining within what was then called the European Community, and on a decent 65% turnout, Roy Jenkins' vainglorious claim at the time that "it puts the uncertainty behind us, it commits Britain to Europe" appears now to be merely a statement of hope over expectation.
The contrary has proved to be the case.
A disquiet runs like a fault line through British public opinion from Parliament to the pub, and so it is that Prime Minister David Cameron has embarked upon a second European referendum campaign asking almost exactly the same question and for precisely the same reason as his predecessor Harold Wilson in 1975.
He wants to hold his party together sufficiently to be able to run his government effectively, just as Wilson did 40 years ago. The main difference between then and now is that all the trouble came previously from radicals who were mostly on the left, while the government's problems today are the go-it-alone nationalists who are mostly on the political right.
There is also the question of British public opinion.
In 1975, most of the establishment was in favour of staying in the "Common Market" we had joined two years earlier. It was a philosophy, a commitment, a vision of post-War international consensus.
But there was opposition and some of it from powerful places.
Enoch Powell resigned as a Conservative MP before the first 1974 election, with a clarion call urging the country to vote Labour because of its opposition to Europe. There were a few other radical right-wing opposing voices.
Most significantly, there was the Labour and trade union movement.
Labour promised in the October 1974 election to hold a consultative referendum if a renegotiation of terms of membership was deemed acceptable by the government.
Roy Jenkins resigned as deputy leader in consequence, correctly suspecting that this was a cosmetic exercise to appease the party's left wing and the-then powerful trade unions.
Wilson undertook to use his "best endeavours" in the renegotiation process, which became a phrase in ironic daily use. In reality, best endeavours boiled down to securing some minor protection for New Zealand butter.
It was enough, however, to secure the passage of the legislation to hold the referendum, which was carried with the support of the majority of Conservative MPs, including their new leader, Margaret Thatcher.
More Labour MPs were opposed than in favour (148 against; 138 for) and 32 abstained.
At a tense special Labour conference, just two months before the referendum, the party voted against Europe by nearly two-to-one, a majority hugely assisted by the fact that 39 of the party's 46 affiliated trade unions voted against. It was a triumph for the left.
It meant that Wilson had to suspend the doctrine of collective ministerial responsibility to allow seven - nearly a third - of the 23 members of his cabinet to campaign against official government policy, (as, in my view, Cameron would be wise also to concede).
It allowed the late Alistair McAlpine, treasurer of the "Yes" campaign, later Treasurer of the Tory Party and later still an enthusiastic member of Sir James Goldsmith's anti-European Referendum Party, to portray Labour's opponents of Europe - Michael Foot, Tony Benn, Barbara Castle and Peter Shore among them - as "dangerous people" who were "virtually Marxist".
British public opinion was led then by the establishment view of the safe option, as it undoubtedly will be in the coming referendum - which Mr Cameron will probably call as early as next May to coincide with Scottish and local elections - despite the shifts in the sands of political opinion in the intervening years.
This is a factor that will help Mr Cameron, as it helped Wilson, to secure the same endorsement.
Mr Cameron has the additional assistance of the support of the Scottish Nationalist Party, whose political significance is considerably greater today than 40 years ago when they voted "No", of the Democratic Unionists and Plaid Cymru (also opposed to Europe in 1975) and the Greens.
Nigel Farage, the leader of UKIP, is regarded by many as being rather too populist to lead a responsible opposition to the massed forces of the political establishment, the City and the business community.
Yet the public support for the case his party has made in succession to the Referendum Party is constant.
There remains a profound antipathy to the European Union, which Mr Cameron will need to address.
The amorphous changes he is seeking in Europe - reforming benefits, bureaucracy and busybody Brussels - can easily be achieved within his meaningless overall objective of resisting "ever closer union".
It may be enough to buy off an obedient electorate. But for how long this time?
Julia Langdon is a political journalist, broadcaster and author. She is the former political editor of the Sunday Telegraph and Daily Mirror.