Some history has been rewritten for us this morning at the Leveson inquiry. For years we have been given to understand that the material seized from Glenn Mulcaire in August 2006 was confused and barely penetrable. The Metropolitan Police were slow to realise the scale and depth of the hacking problem, it was always said, because they didn’t know. And they didn’t know in large measure because they did not spare the resources required to work through three bin bags of chaotic and obscurely-written paperwork.

Today we found that, whatever state the material was in, it was possible within two or three days to compile from it a list of at least 200 targets or victims of hacking across the full range of news subjects, from princes to politicians and from actors to victims of crime. In August 2006, in other words, senior Metropolitan Police officers knew the exact nature and the approximate scale of the problem. Whatever they may say now, that is the very opposite of the impression they have to the Commons media select committee in 2009, 2010 and 2011.

Their defence now, on the basis of the statement of the Met’s counsel today, is that the decision to restrict themselves to one small-scale prosecution, in effect burying the broader issues, reflected two factors: a resources choice and some reluctance to cooperate by News International.

The resources choice was that they could not spare manpower from meeting the terrorist threat because hacking was “not a matter of life and limb”. Yet as they very well knew – and officers expressed concern about this – it was a matter of national security. On the basis of the Mulcaire material it was clear that ministers and MPs were targets, and officers were already raising concern about how widespread hacking was, including presumably at other papers, and by people not journalists.

The problem, in other words, was not trivial and they knew it. It was very grave and they should have been deeply worried. Did they ask for more resources to address it? Did they formulate a long-term-plan to address it? Did they find some way of alerting the public or some other authority to the scale and character of what had been going on? No, no and no.

Instead they formulated a short-term plan to do not very much, and then sat on their knowledge of hundreds of victims of patently large-scale hacking while giving explicit public support to News International’s case that there was one rogue reporter engaged in unauthorised gathering of royal trivia.

Brian Cathcart teaches journalism at Kingston University London and tweets at @BrianCathcart