Despite the population of the United Kingdom not having similar access to guns as our cousins in the United States, lets not forget that we have been subjected to similar events here.
Unfortunately, we have also seen perpetrators of these types of tragedies using a selection of alternate weapons, including Machete's, Grenades, and even a 'Transit' Van in a recent Hit-&-Run spree.
Whilst it is easy to blame 'Guns' and 'Gun Culture', lets not lose sight of the fact that they are just a convenient weapon of choice, and it's the murdering scum-bag using the weapon (any weapon) who is responsible, and not the weapon itself.
Although it isn't an ideal solution, one can only speculate whether the tragic event at Sandy Hook would have been prevented if the school was patrolled by armed security.
Deepest condolences to everyone affected by this tragedy
Andy