Rarely has David Cameron seemed more like the "heir to Blair" than at his Downing Street press conference this afternoon on the terrorist threat from ISIS. He emphasised in his opening statement that the "root cause" of the threat, which was raised today from "substantial" to "severe" (meaning an attack is considered "highly likely"), was not western foreign policy but the "poisonous ideology of Islamist extremism". He said:

Let's be clear about the source of the threat that we face. The terrorist threat was not created by the Iraq war 10 years ago; it existed even before the horrific attacks on 9/11, themselves some time before the Iraq war. This threat cannot be solved simply by dealing with the perceived grievances over western foreign policy, nor it can be dealt with by addressing poverty, dictatorship and instability in the region, as important as these things are. The root cause of this threat to our security is quite clear: it is a poisonous ideology of Islamist extremism that is condemned by all faiths and by all faith leaders. It believes in using the most brutal forms of terrorism to force people to accept a warped worldview and to live in an almost medieval state.

Cameron is right that the threat did not begin with western intervention and will not end with it, but it is worth noting that no less a figure than Eliza Manningham-Buller, the former director-general of MI5, concluded that the Iraq war had "increased the terrorist threat" and acted as "a distraction" from the pursuit of al-Qaeda. Cameron observed that it was broken states and civil wars that allowed jihadists to thrive, while seemingly ignoring that the 2003 invasion helped to create those conditions. He seemed unable or unwilling to recognise why so many previously peaceful Muslims are drawn to extremist ideologies.

On new security powers, while emphasising that he wanted to avoid a "knee-jerk" response to the threat (think of Boris Johnon's call for the presumption of innocence to be abandoned for terrorist suspects), Cameron warned that there were "gaps in our armoury" and that "we need to strengthen them". He announced that he would make a statement in the Commons on Monday on further steps to stop people travelling to fight for ISIS, including new legislation to "make it easier to take people's passports away".

But he added that the threat would only be fully tackled by challenging the "ideology of Islamist extremism head-on, at root, before it takes the form of violence and terror". It is language that will hearten those such as Michael Gove, who have long argued that the government needs to "drain the swamp" that leads non-violent Islamists towards jihadism and not wait for "the crocodiles to reach the boat" (the cause of his fierce disagreement with Theresa May earlier this year). Cameron referred back to his 2011 Munich speech, in which he attacked the "doctrine of state multiculturalism", and vowed to challenge groups that "push an extremist agenda".

It was notable that Cameron sounded cooler on the prospect of British military action in Iraq and Syria than before, emphasising the measures that would be taken on the domestic level. While No.10 has been careful not to rule out the possiblity of joining US-led air strikes (unlike the option of putting "boots on the grond"), it is clear that the last year's defeat over Syria, a war-weary public and the proximity of the general election all mean that Cameron is wary of any greater involvement.

P.S. It's worth highlighting that Cameron, who rarely gives press conferences, took just four questions (three broadcast, one print) after his 10-minute statement. Given the severity of the threat, this seemed inadequate to many present.