Iain Overton is director of investigations at the London-based charity Action on Armed Violence, and author of The Way of the Gun: A Bloody Journey into the World of Firearms.

Do more guns kill more people? This is the million-dollar question that will be at the centre of much commentary following the recent horrors in Orlando, Fla.

One side of the U.S. debate will focus on the argument raised by President Barack Obama – that there needs to be "common sense" gun regulation to stop would-be mass shooters from getting their hands on guns. The other side will argue, as they always argue, that if only there had been more guns in that gay nightclub, they would have had fewer deaths that night (ignoring the fact that if you allowed nightclubbers, with easy access to drink and drugs, to have easy access to guns, the results would be catastrophic).

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To many outside the United States, it seems logical that more guns, indeed, result in more gun deaths. In a country like Japan, where it's hard to own a gun, there are virtually no gun deaths. In the United States, where there are more than 300 million firearms, 8,855 people were shot and killed in 2012 (and guns account for about 70 per cent of all homicides).

However, to be able to show conclusively that more guns lead to more gun deaths is harder. A host of factors come into play when looking at cause and effect; levels of poverty, the rule of law, the number of criminal gangs operating and more. It results in hard-to-explain situations as in Iceland, where there is a very high ratio of gun owners and yet virtually no gun crime.

Such an inability to prove cause and effect lies at the heart of the American gun-control debate. In the absence of proof that guns take, not save, lives, the National Rifle Association pushes back against gun control. Take away our guns, the mantra goes, and you take away our liberty.

Elsewhere, though, when it comes to gun control, what seems to be the sensible thing to do, not hard proof, has won the day.

Twenty years ago – on March 13, 1996 – a tragedy of such sorrow unfolded in the Scottish town of Dunblane that it still has the power to shock today. Thomas Hamilton, a 43-year-old former Scout leader, walked into a primary school with four legally held handguns and killed 17 people, wounding a further 15. Sixteen of the dead were children.

The ensuing debate was to focus on gun-control laws, including massive public petitions calling for a ban on the private ownership of handguns. In response to this, two new firearms acts were passed. They effectively made private ownership of handguns illegal in Britain.

So the question is this: Did the British response to Dunblane work?

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Gun homicides in England and Wales had risen to 66 in 1994 from 26 in 1969. In the year of Dunblane, gun deaths peaked at 84 across Britain. Today, gun killings have dropped to almost a third of that. In England and Wales in 2012-13, the police recorded 30 gun homicides, 12 fewer than the previous year and the lowest figure since the National Crime Recording Standard was introduced in 2002. Given that Britain's population is about 10 million greater than it was in the early 1960s, it seems that the gun controls worked.

It would be wrong, though, to say so conclusively. Britain does not have data sets over time recording how many people survive being shot. Lower mortality figures might just be modern medicine getting better at saving lives. And, of course, Derrick Bird 's killing of 12 people in 2010 in England with a .22-calibre rifle shows that no gun control outside of a total ban is ever going to stop gun deaths.

However, it seems likely that the gun control that resulted from Dunblane has worked. In 2012-13, there were just over 8,000 firearm offences in England and Wales. Knife crime was more than three times that. Of the gun offences, more than half were with air guns or imitation weapons.

The biggest signifier of change, though, might be the role of handguns in crime since Dunblane. In England and Wales in 2012, only 28 per cent of all criminal use of guns involved handguns. They were actually fired in just 11 per cent of these cases – about 250 times.

Compare this with the situation in the United States. In 2012, handguns accounted for about 90 per cent of all firearm homicides where the gun type was recorded.

We can only look at such figures and make our own judgments, and what these will be are deeply influenced by our cultural and societal roots.

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The United States, with its constitutional right to own a gun, is the only country in the world where they have loosened, not tightened, gun laws after a massacre. Their response to Dunblane would, likely, have been to arm teachers or to provide children with bulletproof blankets to hide under. Such a solution would have been met with ridicule in Britain. Instead, Britain opted for no handguns and, so far, no more school massacres have occurred.

Perhaps, as we grieve those who lost their lives in Orlando, it would be worth remembering the lessons learned from other mass shootings farther afield.