Was an IS-inspired gunman responsible for Turkey nightclub attack?

Was an IS-inspired gunman responsible for turning the Reina nightclub in Istanbul into Turkey's Bataclan?

No group has claimed responsibility for the attack, carried out one hour into 2017, and the Turkish government is yet to point the finger - in public, at least.

But the evidence suggests that so-called Islamic State is more likely to have been behind the attack than the Kurdish separatists responsible for last month's killings at a football stadium in the city.

There are other theories to consider.

Religious activists have been campaigning against Christmas imagery and new year celebrations in Turkey.

As part of a recent demonstration, ultra-nationalists held a man dressed as Santa Claus at gunpoint. Investigators may well be considering the possibility that the anti-Christmas campaign influenced this morning’s slaughter.

But many of the characteristics of this morning’s attack were classically IS.

The method: An indiscriminate gun attack against citizens rather than the state or security services, as is favoured by Kurdish groups.

The location: A well-known nightclub packed with hundreds of wealthy Turks and many foreigners too.

The timing: A symbolic moment that recent IS-linked propaganda had promised to mark with bloodshed.

IS certainly has Turkey in its sights - the country which has provided the gateway to thousands of its foreign fighters. Last month it released a gruesome video which appeared to show two Turkish soldiers it had captured being burned alive.

The film included a message encouraging further attacks against Turkey.

But if IS was responsible, there should be a lesson for all countries, including the UK.

We are constantly being told that the group has never been weaker - that its territory is shrinking in Syria and Iraq, that its status will continue to shrivel.

Yet globally, it has never seemed more ambitious - more capable of striking out abroad, or encouraging like-minded followers to launch ambitious self-started attacks.

The Berlin attack last month reminded us that the ideology of IS won’t be beaten simply by re-taking its territory. There’s only so much that airstrikes can achieve.

The threat of IS will endure beyond the fall of Raqqa - beyond the moment coalition forces declare the group 'beaten'.

But we might have to keep speculating about who was responsible for the rampage at Reina.

IS tends not to claim responsibility for attacks it carries out in Turkey. And it rarely says anything when its "soldier" is still on the run - Berlin was an exception.

The uncertainty will only encourage the sense of anxiety in Turkey. Keeping quiet for a little while might have its attractions to whichever group was responsible.