Hopes for a global agreement to outlaw cluster bombs were given a boost Thursday after Prime Minister Gordon Brown called for a total ban on the use of the weapons by the British military.

A statement from Brown's spokesman injected fresh impetus into ongoing negotiations at an international conference on cluster bombs in Dublin.

"The prime minister had issued instructions to our negotiators in Dublin that we should work intensively to ban cluster bombs that cause unacceptable harm to civilians," the spokesman said.

A Downing Street spokesman said Brown had also asked the Ministry of Defence "to assess the remaining munitions in use to ensure that there was no risk to civilians."

Cluster bombs, which were first used in World War II, open in the air and scatter smaller bombs over a wide area. The fact that many fail to detonate on impact make them a risk to the lives of civilians for years.

British forces currently possess two types of cluster ammunitions, the artillery-fired M85 and the M73, which is launched from helicopters.

Campaigners claim British troops used the M85 bombs in the Iraq war in 2003.

The new British stance received a warm welcome from human rights activists and charities.

Anna Macdonald, head of arms control for Oxfam, said: "Britain has at last come in from the cold. We hope that this strong statement from the prime minister will ensure that the UK signs onto the treaty and immediately gets rid of these weapons which maim and kill long after they have been dropped."

Simon Conway, co-chair of the Cluster Munition Coalition and director of Landmine Action, said: "We are glad that Gordon Brown is making good on his previous public commitment to ban cluster bombs."

The Dublin conference, which runs until May 30, is aiming to strike a wide-ranging international agreement that would completely eradicate the use, production, transfer and stockpiling of cluster munitions among signatories.

However, the United States on Wednesday opposed a worldwide ban on cluster bombs, calling instead for "technological fixes" that would make them safer.