As the Kremlin and conspiracy theorists are swift to point out, we do not yet know with absolute certainty who shot down Malaysia Airlines Flight MH17, killing 298 people including at least 9 Britons.

Here’s a brief distillation of what we do know (more detail is available in this excellent summary by the FT):

  • So far in the war in Eastern Ukraine, the pro-Russian separatists have shot down at least 12 Ukrainian aircraft. The Ukrainians, by contrast, have shot down none.
  • Ukrainian anti-aircraft systems are reportedly link to their civil aviation flight control computers, specifically in order to avoid any mistakes between military and civilian targets.
  • The plane was, of course, flying from West to East, further reducing the likelihood that it was mistaken for an aircraft attacking Ukraine from the East.
  • Igor Strelkov, the rebels’ commander, publicly claimed responsibility for his forces shooting down a Ukrainian military plane at the right time in the right place for the plane to have actually been MH17. He has since deleted the post.
  • The pro-Russian separatists today claim that they have no weaponry capable of hitting a plane flying at 10,000m, as MH17 was. However, they have previously published photos of just such weaponry, claiming it to be in their possession. They have also claimed previously to have shot down a Ukrainian plane flying at 6,500m – and a surface-to-air missile capable of hitting that target would also be capable of hitting one at 10,000m. Numerous videos, assessed by the FT, purport to show such a weapons system in the right area and in rebel hands in the last 24 hours.

So, as I began by saying, we do not yet have absolute certainty about who fired the fatal missile. What we do have is a mounting quantity of evidence which points only in one direction: that the Kremlin-backed separatists may well have shot down the airliner, believing it to be a Ukrainian military flight.

If that is indeed what happened, we have a truly monstrous scenario facing us. Yet again, Vladimir Putin’s strategy of destabilising and then dominating Russia’s neighbours will have generated a horrendous price in human suffering (I wrote on its effects in the South Caucusus a few months ago). Yet again, the isolationist myth that “this conflict has nothing to do with us” will have turned out to be tragically naive.

Not only have British lives been lost, but an attack has been made on hundreds of innocent civilians, and peace in Europe is under more severe threat than for many years. As Garvan Walshe argued when Russia annexed the Crimea, allowing such deeds to go unpunished only breeds more atrocities, more aggression and more suffering.

The question, though, is what we can feasibly do? Here are the four options I can see:

1) Sanctions should be drastically extended, and applied much more broadly than simply to a list of individuals in the Russian government and military. (Not to the White House: please don’t give them advance notice to move all their cash this time, thanks).

2) NATO should redeploy in sizeable force to Eastern Europe, effectively moving the old German bases east rather than abandoning them entirely as was recently planned. It should also fast-track the membership of threatened nations such as Georgia into the alliance.

3) Carry out a swift and full Strategic Defence Review with the possibility of Russian aggression against its European neighbours in mind. I argued last month that we Conservatives need to properly thrash out a balance between austerity and defence – this need is growing more urgent by the day.

4) Bring back to life the plans for a missile defence system in Eastern Europe, which were variously ditched and downgraded by the Obama administration. The decision not to go ahead with a purely defensive measure, a shield protecting much of Europe from attack, was interpreted in many places a sign that the Americans were appeasing the Kremlin – it appears Putin may have interpreted it that way, too.

It isn’t necessarily a question of doing one or another – all four combined would be a wise approach.