Mr Brown said talks in Dublin were "very close to agreement" on prohibiting the use of the weapons, which have been blamed for killing and maiming thousands of civilians in war zones.

In a statement, the Prime Minister said the UK would work to secure global support for a new Convention outlawing their use.

He said: "After 10 days of intense talks in Dublin, we are now very close to agreement on a new international Convention prohibiting the use, production, stockpiling and transfer of cluster munitions that cause unacceptable harm to civilians.

"In order to secure as strong a Convention as possible in the last hours of negotiation we have issued instructions that we should support a ban on all cluster bombs, including those currently in service by the UK.

"This Convention will be a major breakthrough, and builds on the UK's leadership on landmines and the Arms Trade Treaty. We will now work to encourage the widest possible international support for the new Convention."

Cluster bomb systems scatter small "bomblets" across a wide area and can prove deadly to civilians - particularly children - who pick up munitions which have failed to detonate on impact.

The Ministry of Defence is reported to have been reluctant to agree to a ban, arguing that cluster munitions were a useful weapon to protect British forces. John Duncan, the British representative at the Dublin talks, acknowledged that Defence Secretary Des Browne and the Prime Minister had "different perspectives" on the issue.

Mr Duncan, the British ambassador for multilateral arms control, said he was confident an agreement would now be reached.

He told BBC Radio 4's The World At One: "This latest statement reflects the Prime Minister and the Government's commitment to deal with this serious humanitarian issue. We now have a basic text which identifies those weapons of concern and the Prime Minister decided that those in the UK Army should be withdrawn from service."