Tight gun controls: the most powerful weapon

But it was the acceleration in the rate of this decline which proved most remarkable: it fell 70 times faster after the new gun laws than before.

Have murderers simply switched methods? While the annual average number of all homicides has increased since June 1996, the rate per 100,000 people has fallen marginally, but can be described as steady. This suggests that partially removing a single type of weapon may not reduce a type of crime committed using many possible means.

This could change if Howard moves to tighten controls over handguns, which he has flagged. Guns have a very high lethality index (or, as it is sometimes indelicately put, a high completion rate) in both homicides and suicides. Had the gun law reforms not occurred, more Australians contemplating suicide - in particular, impulsive young people - might have more easily found a method of instantly ending their lives.

Reliable national data on suicide attempts is not available to examine whether suicide completion rates changed after Port Arthur.

By destroying one-fifth of this country's estimated stock of firearms - the equivalent figure in the US would be 40 million guns - Australians shrank significantly their private arsenal. In 2002-03, Australia's rate of 0.27 gun-related homicides per 100,000 people was one-fifteenth that of the US.