Leading article: Blaming others is not good enough, Ms May

It was New Labour ministers who introduced the doctrine of "when under pressure, blame your civil servants". But Conservative ministers are taking it to new heights, none more so than the Home Secretary, Theresa May. Her statement to the Commons yesterday on the relaxation of border controls over the summer was a classic of its kind. Great was her shock and her anger when she discovered it had happened. But no, she hadn't ordered such a gross dereliction of duty by border officials, nor had she even nodded it through implicitly. What was more, heads had already rolled in the form of the suspension of Brodie Clark – head of the UK border force – and two other officials.

Maybe, in terms of the pinning of "blame" pursued so arduously by MPs these days, Ms May is innocent. Only full questioning by the internal investigation now under way will tell.

It's perfectly possible that officials, under severe pressure of staff shortages and growing queues of angry passengers, did decide to nod through a sizeable number of arrivals without the proper checks. It's also possible that they thought – and their bosses believed – that such measures were acceptable to break out of an impossible contradiction between rising demands and dwindling resources.

What was so disappointing about the Home Secretary's statement, as indeed with most of her policy announcements in the past year, was the tone of animosity and suspicion against people coming into this country. To her, they seem an alien group of would-be terrorists or, worse, "economic tourists".

In reality, most of the people arriving here are either tourists helping an economy badly in need of their revenues, or people on business. The largest proportion are from the EU, with rights of passage and work. The problem with the anti-foreigner rhetoric adopted by Theresa May and regrettably unquestioned by the opposition – which seems to see this simply as an opportunity to catch her out – is that it fails to distinguish between, on the one hand, threats to security from terrorists and criminals, and, on the other, problems caused to society by illegal immigration for economic ends. They are different and require separate measures of border controls. A little latitude in enforcement is the oil that enables heavy machinery to move with efficacy.

This was presumably why Ms May did sanction, without apparently informing the Prime Minister (it's clearly a game of "pass the blame" now), pilot schemes to allow looser checks on less suspicious groups in order to allow tougher controls on more likely threats.

But that in turn may have sent out the wrong signals to her civil servants.

You can't have it both ways. The tradition of Parliament is that ministers answer to it for the actions of their departments. In the past, that presumed political responsibility even when they were not directly responsible. Today, they try to draw a distinction between what they personally sign for and what their civil servants do.

It's a nice distinction, but a misleading one. The job of a minister is not just to set policy for his or her department, but also to establish the culture in which it operates. It's no good the Home Secretary declaring fierce aims in public if she does not communicate this as the priority in the choices made below her. The suspicion in this case is that the actual culture of most departments of Government at this moment is one of cut budgets, reduced staff and "let's just manage as best we can". In that culture, officials were bound to take the easy way out when presented with throngs of angry arrivals.

This is not to excuse a widespread relaxation of rules which could have let through putative terrorists. But effective policy can only come from effective ministers.

Just blaming officials is no route to that.