This week will mark two important occasions for me. The first takes me back 10 years to one of Britain's worst acts of gun violence. The second will be the start of a crucial phase of a campaign aimed at reducing future gun violence worldwide.
Today is the 10th anniversary of the shootings at Dunblane Primary School, when 16 children and their teacher were killed by Thomas Hamilton, who entered the gymnasium and opened fire on the class.
My five-year-old daughter Sophie was among the dead.
It took Hamilton just three minutes, firing over 100 rounds of ammunition from a single handgun, to create this horrific scale of death and injury. Such is the destructive power of guns.
Immediately after Sophie's death, I knew that I wanted to do something to reduce the risk of any other person coming to harm through the misuse of guns.
My reaction to the shootings in Dunblane was much the same as that of many others, including the families of the other victims and the majority of the British people. If guns were less easily available they would be less likely to be misused, and so everything possible should be done to limit access to them.
We campaigned to change the law in Great Britain so that it wouldn't be possible for another person such as Hamilton to accumulate an arsenal of handguns, legally, because he wanted to pursue a so-called sport, target shooting. In 1997, the private ownership of handguns was banned. But the lax attitudes of our Government and others to the arms trade are contributing to the proliferation of guns around the world, leading to escalating gun violence in those countries least able to deal with the consequences.
It is important not only to be concerned about what is happening in your own country but also to recognise the scale of this problem. The world is awash with firearms - as many as one gun for every 10 people. Across the planet, 1,000 people are killed every day. The majority of the victims are not soldiers but civilians, many of them women and children.
Many millions are injured, live in fear of gun violence and have restrictions placed on their lives because they can no longer get access to education, health services, markets and workplaces.
The lack of controls over these weapons allows them to flow too easily from one region to another. Often they flood into conflict zones, fuelling further mayhem, and spreading the violence into neighbouring regions as excess weaponry leaks across borders.
On Thursday I will be taking part in the launch of a campaign to mark the One Hundred Day countdown to a UN conference in New York, where member states will discuss whether to agree to stronger controls on the global small arms trade. Without curbing this trade, every year hundreds of thousands of people will continue to lose their lives to guns; many more will find their lives blighted irreversibly.
An international arms trade treaty would go some way to ensuring that no one - no government, no company or individual - would be allowed to export guns where they might be used to kill and injure innocent civilians.
A significant number of countries, including the UK, have indicated that they are in favour of a legally binding arms trade treaty, but there are a smaller number, most notable of which is the United States, who continue to oppose it. They appear unconcerned about the consequences of not getting this lethal trade under rigorous control.
However, even the UK is failing to use its influence at the UN to push for tighter controls on the arms trade. The UK started as one of the leaders behind the idea of the treaty but has since failed to show leadership at the UN to make it a reality. They need to do more.
The One Hundred Day Countdown will be a time when every effort should be made to convince governments of the great benefits that strict control of the arms trade would bring to the world. Everybody can contribute by writing to the Government to indicate their support, or by becoming one of the Control Arms Campaign's Million Faces. People from around the world have been submitting their photographs to show their support for arms control.
This week, most of my thoughts will be focused on Sophie. In the 10 years since she and her classmates died, another 3 to 4 million people have fallen victim to gun violence. I hope that as a result of what we do during the next hundred days it will be possible to look back in 10 years' time and view it as the decade when something was eventually done to remove the scourge of the gun from around the world.
The Million Faces petition is at www.controlarms.orgReuse content