There are few genocides more clearly established than that suffered by the Armenians in 1915-16, when half the race was extinguished in massacres and deportations directed by the “young Turk” government. Today you can be prosecuted in France and other European countries for denying it. But the world’s most influential genocide denier, other than Turkey itself, is the British government, which has repeatedly and adamantly asserted that there is not sufficient evidence that what it terms a “tragedy” amounted to genocide. Now, thanks to the Freedom of Information Act, we learn (in the words of FCO memos to ministers), that commercial and political relations with a “neuralgic” Turkey have required abandonment of “the ethical dimension”.

For the past 10 years, various Foreign Office ministers, from Geoff Hoon to Lord Malloch-Brown, have told parliament that “neither this government nor previous governments have judged that the evidence is sufficiently unequivocal to persuade us that these events should be categorised as genocide, as defined by the 1948 Convention”. This would have come as a shock to the architects of the 1948 Convention (for whom the Armenian genocide was second only to the Holocaust), as well as to the wartime British government, which accused the Turks of proceeding “systematically to exterminate a whole race out of their domain.” (Winston Churchill actually described it as “an administrative holocaust…there is no reasonable doubt that this crime was executed for political reasons”).

What does the Foreign Office know that eluded our government at the time as well as the drafters of the Genocide Convention, not to mention the International Association of Genocide Scholars, the US House Foreign Affairs Committee and at least nine other European governments? The Freedom of Information Act has now unravelled this mystery.

The Armenian Centre obtained several hundred pages of hitherto secret memoranda, accompanied by an astonishing admission that there was no “evidence” that had ever been looked at and there had never been a “judgment” at all. Parliament had been misinformed: as the Foreign Office now admits, “there is no collection of documents, publications and reports by historians, held on relevant files or any evidence that a series of documents were submitted to ministers for consideration”. In any case, ministers repeatedly asserted that “in the absence of unequivocal evidence to show that the Ottoman administration took a specific decision to eliminate the Armenians under their control at the time, British governments have not recognised the events of 1915-6 as genocide”.

That was the answer given by the government during the House of Lords debate on the subject in 1999. The thinking behind the genocide denial is revealed in an internal memorandum to ministers (Joyce Quinn and Baroness Symons) just before the debate: “HMG is open to criticism in terms of the ethical dimension, but given the importance of our relations (political, strategic and commercial) with Turkey…the current line is the only feasible option”.

Nobody noticed that this “current line” was a legal nonsense. To prove genocide you do not need unequivocal evidence of a specific government decision to eliminate a race – neither the Nazis nor the Hutu government in Rwanda ever voted to do so or recorded any such decision. Genocidal intentions are inferred from what governments do and from what they knew at the time they did it, and it was obvious to everyone in Armenia (including German diplomats and missionaries, then allied to Turkey, and neutral US ambassadors) that the deportations had turned into death marches and the massacres were influenced by race hatred fanned by the governments “Turkification” campaign. The internal documents show that the Foreign Office has never had the slightest interest in the law of genocide: its stance throughout is that HMG cannot recognise this particular genocide, not because it had not taken place, but because realpolitik makes it inconvenient.

There is no suggestion in these documents that expert legal advice was ever sought before ministers were wrongly briefed on the law of genocide. The definition of the crime includes “deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part” – a precise description of the Ottoman government’s orders to deport 2 million Armenians to the Syrian desert, in the course of which half died from murder or starvation. Courts in the Hague have actively developed the law relating to genocide in recent years, but the Foreign Office memos make no reference to this: its only concern is that nothing should be said by ministers to discomfort a Turkish government which it describes as “neuralgic” about its accountability.

The documents reveal that Foreign Office officials have actively discouraged ministers from attending memorial services for Armenian victims and from including any reference to this genocide at Holocaust memorial day. There is a note of self-congratulation at having prevailed upon Mrs Beckett, Mr Hoon and Mr Howells to absent themselves from the Armenian genocide memorial day in 2007, and the same attitude was exhibited in 1995, in a document that records how conservative minister Douglas Hogg was similarly persuaded against attending an All Party memorial service on the 80th anniversary of the first massacre. It is no business of the Foreign Office to discourage ministers from attending memorial services for victims of crimes against humanity, and the behaviour evidenced by the internal memos reflects badly both on the officials and upon the ministers who so readily allowed themselves to be dissuaded.

One notable feature of these hitherto secret documents is how government ministers parrot their Foreign Office briefs in parliament word for word and never challenge the advice provided by diplomats. No one has ever pointed out, for example, that the “not sufficiently unequivocal” test is oxymoronic – evidence is either equivocal or it is not. It cannot be a little bit unequivocal.

The other routine excuse for denying the genocide has been that “it is for historians, not governments, to interpret the past”. This “line” was described in 1999 as “longstanding”. But genocide is a matter for legal judgment, not a matter for historians, and there is no dispute about Armenian genocide among legal scholars. But the Foreign Office ministers repeatedly insist that “interpretation of events is still the subject of genuine debate among historians”. This “line” was stoutly maintained until last year, when it was placed on the Downing Street website in response to an e-petition and provoked angry replies from the public. The minister, by now Jim Murphy, was highly displeased, and became the first to demand to know just what evidence the Foreign Office had looked at to decide that it was “not sufficiently unequivocal”.

The Eastern Department had looked at no evidence at all. In great haste they came up with three historians – Bernard Lewis (who had been prosecuted in France for denying the genocide, but then told Le Monde that he did not dispute that hundreds of thousands of Armenians had died); Justin McCarthy (a Louisiana professor whose pro-Turkish work was sent to Keith Vaz by the Turkish ambassador) and Dr Heath Lowry, who provoked the “Heath Lowry affair” at Princeton after it accepted funds from the Turkish government to endow his “Ataturk Chair” and he was then exposed as having drafted genocide-denial letters for its ambassador. It is astonishing, given the number of British historians, from Arnold Toynbee onwards, who have no doubts on the subject, that the FCO should grasp at the straw of three controversial Americans.

Murphy was later told by the head of the department that they had stopped “deploying this line” because “we found that references to historians tended to raise further questions”. The Minister was easily pacified – the old mantra that “neither this government nor previous governments have judged that the evidence is sufficiently unequivocal” was read out on his behalf by Lord Malloch-Brown, despite the fact that no government had actually “judged” or had received any evidence at all.

Parliament has been routinely misinformed by ministers who have recited Foreign Office briefs without questioning their accuracy. HMG’s real and only policy has been to evade giving any truthful answer about the Armenian genocide, because it has abandoned “the ethical dimension” in the interests of commercial and political relations with a Turkish government which it acknowledges to be mentally unbalanced about this issue.

In August 1939 Adolph Hitler infamously exhorted his generals to show no mercy to the Polish people they were preparing to blitzkreig, because “after all, who now remembers the annihilation of the Armenians?” If the ethics free zone in the Foreign Office has its way, nobody in the UK will remember them either.

Geoffrey Robertson’s opinion on the Armenian Genocide and on the FCO policy documents is obtainable free of charge from j.flint@doughtystreet.co.uk.