London , England ( CNN ) -- A law banning the use , production , and stockpiling of cluster munitions came into effect Thursday in Britain . British Prime Minister Gordon Brown urged other countries to enact similar legislation , saying a global ban is needed to fight such `` cruel and indiscriminate weaponry . '' The Cluster Munitions ( Prohibitions ) Act received royal assent Thursday after it passed through both houses of Parliament . `` Cluster munitions cause immense suffering to civilians caught in conflict zones , and leave a deadly post-conflict legacy for future generations , '' Brown said in a statement . `` I am hugely proud that with this bill receiving royal assent , Britain is leading the world in banning the use of these munitions and moving to end the harm they cause . '' The act also bans direct financing of cluster munitions production . The British government has already said it plans to work with the financial sector , non-governmental organizations and others on a voluntary code of conduct to prevent indirect financing of the weapons . Cluster munitions , which break apart in flight to scatter hundreds of smaller bomblets , are described by the International Committee of the Red Cross as a `` persistent humanitarian problem . '' Most of a device 's bomblets are meant to explode on impact , but many do not . Credible estimates show the weapons fail between 10 percent and 40 percent of the time , leaving civilians at risk of harm from unexploded ordnance , the ICRC says . During the 34-day war in Lebanon in 2006 , the United Nations estimated that Israel dropped 4 million bomblets , 1 million of which may not have exploded , according to the ICRC . More than 250 civilians and bomb-disposal operators have been killed or injured by them in southern Lebanon since the war ended . Cluster bombs were also used in the 1999 war in Kosovo . In more than 20 countries , according to the ICRC , cluster bombs have created lasting `` no-go '' areas , rendering them as dangerous as minefields . Laos is the most affected country , where millions of bomblets dropped during the Vietnam War continue to kill civilians more than three decades later . Britain is among 104 nations that have agreed to a treaty banning all cluster bombs . Thirty of those nations have ratified it , and Brown said he hoped passage of the new law would pave the way to U.K. ratification of the ban . Four of the world 's biggest cluster bomb makers -- Russia , China , Israel and the United States -- have not signed the ban , claiming the devices are a vital part of their defense strategy . `` We want all other users and producers of these munitions around the world to follow in our footsteps , '' said Brown . `` We want nothing less than a full global ban on cluster munitions , with all countries signing up to the international convention . There can be no place in the international community for cruel and indiscriminate weaponry such as cluster bombs . '' In addition to calling for a total , immediate ban of the weapons , the treaty calls for strong standards to protect those injured . It urges that contaminated areas be cleaned up quickly and weapons immediately destroyed , the Cluster Munition Coalition has said . The agreement , due to come into force in August , also requires the destruction of stockpiles of the weapons within eight years , the coalition has said .
New UK law bans use , production , and stockpiling of cluster munitions . Cluster bombs break apart in flight scattering hundreds of smaller bomblets . ICRC describes bombs as a `` persistent humanitarian problem '' 104 countries have agreed to a treaty banning all cluster bombs .