The response of the Prime Minister, other ministers and officials to the outbreak of foot-and-mouth disease reported on Friday night has been vigorously applauded. Hilary Benn, the Environment Secretary, has not been slow to point out the contrast between the reaction in Whitehall on this occasion and that witnessed six years ago. The tests on the affected farm were completed very swiftly this time, the movement of animals across the country banned in hours and not days, and the machinery of emergency planning – already employed in recent weeks to cope with apparent terrorist attacks and then floods – was promptly mobilised. Gordon Brown’s instant willingness to curtail his summer holiday certainly sent a stronger signal of the importance of this event than his predecessor managed in 2001.

All of this is true, but it should not be the cause for premature self-congratulation. The handling of the last foot-and-mouth epidemic was an expensive shambles of the highest order. The old Ministry of Agriculture was almost staggeringly slow to act and the disease was allowed a head start as a consequence. The Army was not called in until the situation was out of control. Much of the countryside became a string of funeral pyres with devastating results for the regions involved and billions of pounds of public money were squandered because of this collective incompetence. It would have been an outrage if lessons had not been learnt and a scandal if past errors had been repeated. It is too soon for Defra to be hinting that it has passed this test with flying colours. The real challenge is yet to come.

Much the same could be said about the rush to judgment as to precisely how this strain of foot and mouth was passed on to a small number of cattle grazing in a rural corner of Surrey.

It seems almost certain that the outbreak was triggered by a leak of foot-and-mouth from the Pirbright centre shared by both the Institute for Animal Health and Merial Animal Health. The strenuous protestations by the leadership of the Institute that all of their bio-security procedures have been followed to the letter has reinforced the suspicion that Merial, which last month produced a batch of vaccines using the strain linked to the cattle which were infected, is the most plausible source of this disease. This has led to the insinuation in certain circles that because the company concerned seeks to make a profit in its marketplace and, worse still, is ultimately owned by a large business based in the United States, then it must have dubious standards of security. Others, including David Cameron, indicated yesterday that, whatever the details of this affair, the Government must ultimately be at fault.

This is crude and crass. There are a number of possible explanations as to how foot-and-mouth might have escaped from the Pirbright laboratories, ranging from flooding to human error to extraordinary misfortune. It will not be long before the report on the site commissioned from Professor Brian Spratt of Imperial College, London University, provides some interim conclusions. Until then, it would be profoundly unfair and unwise to assume that, because Merial is a private institution with a corporate base in the United States, then it might have been careless. The immediate priority, as the Prime Minister rightly observed yesterday, must be to contain, then control, then eradicate this disease. With luck, the nature of its source means it will not have travelled widely throughout the country. Once that is established, and only then, should a blame game be initiated.