As the UN general assembly opens this week, it has its best opportunity in years to make a life-saving difference to people all over the world. An opportunity to stop human rights abuses, limit the threat of terrorism, and reduce suffering for millions. The opportunity is a draft resolution for an international arms trade treaty that would place tough controls on sales.

The treaty would make it illegal to sell weapons to human rights abusers; make it harder for weapons to end up in the hands of criminals and terrorists; and help regulate a trade that is spiralling out of control – $900bn spent on defence versus only $60bn on aid. Every day over 1,000 people lose their lives through armed violence.

We have seen the appalling consequences recently in the Middle East: the Israeli army flattening civilian targets with precision-guided 1,000lb “bunker-buster” bombs and forcing almost a million people to flee their homes; Hizbullah rockets fired into civilian areas in northern Israel, killing people and forcing others to leave. Both are war crimes, and largely perpetrated with weapons imported from other countries.

Israel’s military hardware, including its deadly cluster bombs, is overwhelmingly American-made. And hi-tech British components were used in the Apache helicopters that have fired rockets at cars on crowded streets, and the F-16s that devastated southern Lebanon. For its part, Hizbullah doesn’t manufacture the Katyushas or Khaibar-1 missiles it fired indiscriminately into Israel.

Six-year-old Abbas Yusef Shibli picked up a cluster munition while playing with friends because it looked “like a perfume bottle”. When it exploded in his hand, he suffered a ruptured colon, a ruptured gall bladder, and a perforated lung.

Nicaragua, my birthplace, is still awash with weapons, the legacy of a bloody conflict – fuelled by the US arming the Contras – in which more than 40,000 civilians were killed. Nicaragua is now one of the poorest nations in the western hemisphere.

For decades, the US provided millions of dollars in military aid to oppressive governments in Latin America; many of those countries now have high levels of armed violence. As a human rights campaigner, I have advocated on behalf of countless victims of conflict, from Latin America to the Balkans to the Middle East. I can attest to the devastating effect on the civilian population, particularly on women and children.

Some nations still try to block the treaty’s progress – though their arguments are flawed. The resolution from Britain, Finland, Japan, Argentina, Australia, Costa Rica and Kenya, would not undermine states’ sovereignty or ability to lawfully defend themselves with force. It would not hamper law enforcement to provide security for their citizens. Arms importers and exporters would simply have a clear set of rules to abide by, rather than the current hotch-potch of uneven and conflicting regulation.

The treaty would promote real security. It would help to stop armed groups that pay no heed to international law equipping themselves. An Amnesty International report last year detailed shipments of more than 240 tonnes of weapons from eastern Europe to governments in Africa’s war-torn Great Lakes region, and on to militias involved in massacres, mutilation and mass rape.

More than 50 countries have voiced support for an arms trade treaty, but to make it happen we need a majority of the 192 member states. Today Britain hosts a meeting of diplomats to discuss tougher arms controls. For once the international community can act pre-emptively to prevent carnage, not be forced to mop up afterwards. It is an opportunity that the UN must seize.

Bianca Jagger is goodwill ambassador for the Council of Europe