Eden's sweeping thoughts on the future of Britain were set out in a remarkable private memorandum to Cabinet colleagues which is full of echoes for today's politicians. Although it is 37 years old, it has only been released to historians in the past few weeks and, but for a recent change in government policy, it could have remained secret for a further 60 years or more.
The first 'lesson of Suez', Eden wrote, was that 'if we are to play an independent part in the world . . . we must ensure our financial and economic independence'. And 'since we have no raw materials but coal, this means that we must excel in technical knowledge'. Too many of the country's scientists, and too much government money, was being devoted to defence, Eden wrote. Many naval bases abroad should be closed, and the army in Germany cut in half.
''The most anxious fact on the home front,' he wrote, 'is I think the alarming increase in the cost of the Welfare State.' While spending on education could be justified as underpinning industry, much of the rest was 'less directly related to our struggle for existence', while high taxation was driving entrepreneurs and scientists abroad.
Concluding, Eden said that Britain was likely to be driven towards closer co-operation with Europe, but he warned, prophetically, that the European governments might not welcome a British approach. The timing and conviction of Britain's overtures to Europe would be all-important.
As a record of a prime minister's views on his country's future as it emerged from crisis, it is a document of great importance. Keith Kyle, the historian of Suez, describes it as Eden's 'last will and testament'. Professor Peter Hennessy, an authority on post-war government, believes that 'everybody who writes about Suez, about Eden, or about Britain's role in the world in the Fifties and Sixties is bound to quote it, whether they be academic historians writing books or undergraduates turning out essays'.
Yet Mr Kyle and Prof Hennessy have only known about the 'lessons of Suez' document for a few weeks, and until this year there was no plan to release it to the public for decades, possibly not until after the year 2056.
Public Record Office (PRO) document PREM 11/1138, as it is now known, is one of roughly 6,500 state papers or files which the Government has opened in the past year, overruling decisions to hold them back for security or other reasons. The documents cover an enormous variety of issues, from Rudolf Hess to early Commonwealth conferences, from allegations that RAF pilots were held prisoner in Russia after the war to Anglo-Irish relations in 1921, from the Nazi occupation of Jersey to Pearl Harbor. Thousands more documents are in the pipeline, to be released in the coming months.
Historians who have been examining the new releases at the PRO in Kew, south-west London, react with enthusiasm and occasional excitement. Mr Kyle, for example, has been able to confirm that barely six weeks before the Suez crisis erupted, Nasser, the Egyptian leader, wanted to come to London for face-to-face talks with Eden.
The trigger for the release of all these papers was an invitation to historians last year from William Waldegrave, the minister responsible for open government, to identify secret files which they felt should be opened.
Normally, the papers of the various government departments, when they are no longer useful to officials, are 'weeded' to remove uninteresting material and then closed for 30 years, after which they are opened to public scrutiny at the PRO. Certain categories of papers are excluded, notably those relating to national security, those which might cause distress or danger to individuals and those containing information acquired upon a guarantee of confidentiality.
For years historians had complained that far too much was held back, and they were able to identify cases where the reasons were ludicrous. The file on civil unrest in Tonypandy in 1911, for example, was kept secret for 75 years and it was long suspected that the reason was to protect the reputation of Winston Churchill, then Home Secretary. When the file was opened, it was found that the 'sensitive' material it contained related to special police overtime arrangements.
Another example was raised recently in the House of Lords. The records of a defunct Foreign Office body, the Information Research Department, remain closed after 40 years although Lord Mayhew, who ran the department as a young man, insisted to fellow peers last month that they contained nothing sensitive.
He said the Soviet Union knew what the department was up to, 'because one of my less happy actions at IRD was to appoint to this secret department an official who showed at interview a most remarkable grasp of Soviet propaganda. This was Mr Guy Burgess.'
When Mr Waldegrave, keen to prove his commitment to British glasnost, asked historians to name files overdue for opening, the response was swift and effective. After a meeting in London last November, organised by the Institute of Contemporary British History (ICBH), a list was drawn up and passed to the minister.
The result has been impressive, and it has been made possible by a general attitude of greater flexibility. One suggestion made at the ICBH meeting was that, where a long document contained a short passage of sensitive material, an American practice of 'blanking out' should be adopted. A copy would be made with the passage replaced by blank space, and this could then be released.
The idea was accepted and Eden's 'lessons of Suez' is an example. It contains a blank space adorned with the handwritten words: 'Passage deleted and retained under Section 3 (4)'. In all likelihood the missing sentences deal with intelligence; they will remain secret as long as the Government wishes.
Another change has been the abolition of a bureaucratic Catch 22. Government departments wishing to withhold a file past the 30-year limit have to defend their case before an impartial body called the Lord Chancellor's Advisory Committee on Public Records, which includes reputable historians among its members.
The committee, in the past, could challenge officials over any particular file, but in assessing the case they were at a disadvantage: they did not have security clearance so they were not allowed to see what the file actually contained.
That is now to change. The Lord Chancellor, Lord MacKay, announced last month that either the chairman of the committee, or one member (who will presumably be subjected to security vetting), will be allowed to inspect contentious files.
Although untold numbers of files older than the 30-year limit still remain secret, historians are encouraged by the changes and by the continuing clear-out of papers. But does it all matter? Can a load of tatty documents in dusty files really be worth all this administrative effort and all this ministerial and parliamentary time?
Brian Brivati, secretary of the ICBH, offers a spirited response. 'The importance of this development extends beyond the narrow confines of professional historians; it is a process of maturing as a democracy,' he says. Some files show past governments behaving badly, and later generations of politicians should not be allowed to protect them. In other cases openness serves the Government's interests, for the truth in the files can kill off conspiracy theories encouraged by secrecy.
He also has a more basic argument: 'Historians have to earn a living. I do not think this is such a ghastly thing to admit. The PRO is for many of them the source of their livelihood.'
This week in London the ICBH will hold a second conference on PRO releases, sponsored by the Independent on Sunday, to review the impact of the Waldegrave initiative and compile a fresh list of files still waiting to be opened.