After yesterday’s meeting of the government’s crisis group, Cobra, it was announced that the UK would be sending 750 troops and a hospital ship to Sierra Leone to help combat the spread of Ebola there. It subsequently transpired that the deployments were already in progress, and that many of the troops were there or on their way there.

Along with making known that hospitals throughout the UK had contingency measures in place to deal with any incidence of Ebola here, this was the first official government response to the epidemic now threatening west Africa. It came on the day that the western world seemed suddenly caught up in the epidemic as it had not been before.

Thomas Duncan, a Liberian national, became the first person to die of the disease in the United States. The Spanish stepped up efforts to trace contacts of a nurse who contracted the disease while helping to care for an Ebola patient in a Madrid hospital – a precautionary measure included putting down her family dog – and the US announced that it would screen airport arrivals from affected countries.

The US measures immediately prompted questions here about why the UK was not introducing airport screening too. The answer sounded a bit defeatist but was not unreasonable. Huge numbers of people arrive at UK airports every day, and many have a raised temperature after a long journey. The incubation period for Ebola can be up to 21 days, so that even the most effective screening would probably not identify someone with the disease. Airport screening would be an enormous and largely counterproductive effort. To which might be added the general inefficiency of UK border controls in apprehending suspected terrorists and others wanted by the authorities.

A more pertinent question might concern the government’s decision to send in the army. In a way, dispatching troops to Sierra Leone is a perfect example of the thinking we have so often seen in relation to terrorism: we are fighting over there so as not to have to fight over here. The UK has a special relationship of a kind with Sierra Leone, which offers a rare example of successful British military intervention – in the 1999-2000 civil war – so UK military personnel might be more familiar and welcome there than in other affected countries.

But is building an emergency hospital – which is one of the army’s tasks – and treating patients offshore really something the military ought to be doing? Where is the Department for International Development in all this, and the UK’s vast charity sector? In war zones, such as Afghanistan, there can be friction between development types and the military whose protection is at once a necessity and a liability. Here, the tensions might work the other way around, with civilian organisations effectively sidelined.

It can no doubt be argued that the military are experts in providing emergency and temporary facilities and no one can get a job done like the army. But the top brass have been complaining about cuts in numbers of deployable troops, and disease containment is not obviously something the military should be doing, when there is still a (small) presence in Afghanistan and reinforcements may be needed for the international effort against Islamic State (Isis).

So could there be another dimension to this deployment – as a contingency, say, against the inability of the Sierra Leone authorities to enforce a quarantine regime, or even against a possible breakdown of law and order. And if such a contingency is – even distantly – envisaged, is Sierra Leone being regarded as something of a test-bed or training exercise for what – in the extreme – must be prepared for here?