The cluster 'bomblets' can act as landmines if they fail to detonate
The UK government is to join more than 100 nations in Dublin this week for talks that campaigners believe could lead to the most significant disarmament treaty for a decade.
If successful, supporters say the negotiations will decide the wording for an international agreement to ban cluster bombs that ''cause unacceptable harm to civilians''.
These munitions have been used in battle for more than 40 years in 30 countries, and were last deployed by the Israelis in Lebanon in the summer of 2006.
Cluster bombs are made up of a big container which opens in mid-air and drops hundreds of individual sub-munitions or "bomblets" over a wide area. They usually explode once they hit their target.
The types of cluster munitions we intend to retain are legitimate weapons with significant military value
Defence Secretary Des Browne
It was the enormous damage caused to civilians during the month-long conflict between Israel and Hezbollah that led a number of governments, led by Norway, to back the Oslo Process, which aims to come up with a treaty by the end of 2008.
The Dublin meeting, set to begin on Monday, is the penultimate step.
And while the UK government has shown a commitment to the process, it is strongly opposed to an outright ban.
Instead, the government has stated it wants an exemption for the newest generation of cluster munitions.
In a statement to Parliament in March 2007, Defence Secretary Des Browne said: "The types of cluster munitions we intend to retain are legitimate weapons with significant military value which, as a result of mitigating features, is not outweighed by humanitarian factors."
In this case, the "mitigating factor" is so-called smart technology, which Britain says minimises civilian casualties.
But Mr Browne's assurances have not convinced some governments and campaign groups.
Problems can arise when the sub-munitions or "bomblets" are used in populated areas but fail to go off.
If these cases, they can sit on the ground for years, effectively becoming landmines.
Close up footage shows cluster bombs exploding
Victims are often children, who mistake them for toys.
"These bomblets are the size of a soft drink can or tennis ball and spread hundreds of metal fragments that tear apart flesh and sever limbs," said Thomas Nash, of the Cluster Munition Coalitions (CMC), an umbrella organisation for a number of anti-CM charities.
"As if that weren't bad enough, cluster bombs consistently leave deadly duds on the battlefield that act like landmines. This problem not only affects lives but also shatters livelihoods because the unexploded cluster bombs make it dangerous or impossible to use land."
Britain got rid of its most unreliable sub-munitions - the RBL 755 and the multi-launch rocket system M26 munitions - last year.
However, it chose to keep "smart" sub-munitions like the M85, last used in Iraq in 2003, because they contain self-destruct mechanisms.
Mr Browne said this technology significantly ''reduces the risk of harm to civilians''.
The government points to tests that suggest failure rates are as low as 2%.
Campaign groups strongly dispute this figure, saying those tests were carried out by the manufacturers themselves.
"Claims by the UK that cluster munitions have a 2% failure rate are not convincing at all, in fact the evidence shows they're untenable," said the CMC's Mr Nash.
"Research in Lebanon, undertaken by experts including the Norwegian defence research establishment, which itself used to conduct tests of self-destructing cluster munitions, showed the failure rate was more like 10%.
"The UN team responsible for the clearance in Lebanon have supported these findings."
Figures from the charity Landmine Action estimate that in 2003, the UK and US used around 13,000 cluster munitions containing an estimated 1.8 million to 2 million sub-munitions.
Ten years after it championed a treaty banning landmines, the UK has a chance to do the same with cluster bombs - but instead it is spinning a cluster bomb con
Simon Conway Landmine Action
The CMC says cluster munitions caused more civilian casualties in Iraq in 2003 than any other weapon.
The government insists that its testing is accurate, but says it takes the various studies seriously.
A number of leading charities, including Oxfam, Amnesty International and Human Rights Watch, have also accused the UK government of attempting to re-name one of its two remaining cluster bombs in an effort to get around any future ban.
In a joint statement they said: "As recently as 26 November 2006, the government listed the CRV-7 rocket system, which can deliver 171 M73 bomblets, as a cluster munitions. But on 16 July 2007 the government said the CRV-7 was no longer a cluster bomb."
Simon Conway, director of Landmine Action, accused Britain of "a deeply cynical move".
Cluster bombs were used most recently by Israel in 2006
"Ten years after it championed a treaty banning landmines, the UK has a chance to do the same with cluster bombs - but instead it is spinning a cluster bomb con."
The government said each CRV-7 rocket contained nine M73 bomblets, not 171.
The government stated it was not a cluster munition because of its "direct-fire capability, a small defined "footprint" and because each rocket contains only nine bomblets.
"Taken together it is not likely to pose an unacceptable post-conflict humanitarian risk," a spokesman said.
As the Dublin talks kick off, the next two weeks will undoubtedly prove a diplomatic assault course, as governments seek to grapple with, stumble over or simply avoid the thorny issues of exemptions, definitions and timetables.
From the point of view of campaigners, anything less than a total ban would fail to protect the very civilians that the treaty is supposed to save.
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