A leading human rights group has discovered a banned British-made cluster bomb used by the Saudis in their war on Yemen.

Amnesty International found the undetonated bomb in a remote village in northern Yemen.

The controversial BL-755 cluster bombs, banned decades ago, were built in the 1970s by the British company, Hunting Engineering, and designed to be deployed on UK-made Tornado fighter jets.

Each bomb has a cluster of 147 little bombs inside that scatter over a wide area when dropped. Some do not explode until agitated by unsuspecting civilians when they take their toll.

Amnesty says a Yemeni herdsman in the village located several miles from the Saudi border in Hajjah governorate warned the rights group that “in the area next to us, there are bombs hanging off the trees.”

Amnesty says the British government needs to destroy its cluster bombs and help find those it sold in the past.

Britain is believed to have sold many such munitions, which are prohibited in over a 100 countries, since the 1980s and 90s to Saudi Arabia and the United Arab Emirates (UAE) – a Saudi ally in its war on Yemen.

It also sold scores of Tornado jet fighters to Riyadh ever since.

Amnesty International’s head of UK Arms Controls, Oliver Sprague, has reportedly said it would be an “absolute scandal” if British personnel had been in any connected to the incident.

“Cluster bombs are one of the nastiest weapons in the history of warfare, rightly banned by more than 100 countries, so it’s truly shocking that a British cluster munition has been dropped on a civilian area in Yemen,” he said.

A Yemeni man inspects the rubble following a Saudi airstrike on May 31, 2015 in the al-Thawra sport city, located north of the Yemeni capital, Sana’a. (AFP)

"Given that this type of cluster bomb is very likely to have been used in combination with Tornado war planes which the UK has also sold to Saudi Arabia, there’s even a possibility that British support personnel might have been involved in the cluster bombing of Yemen. This would be an absolute scandal if confirmed.”

Yemen has been under airstrikes by Saudi Arabia since the regime in Riyadh launched its fatal campaign against the impoverished country on March 26, 2015, in a bid to undermine the Houthi Ansarullah movement and restore power to Saudi-backed former president Abd Rabbuh Mansur Hadi. More than 9,400 people have been killed in the Saudi airstrike ever since.