On Saturday, an aircraft of the Royal Saudi Arabian Air Force attacked a funeral in Sanaa, the capital of Yemen, killing more than 140 people, and injuring more than 500 others. On Sunday, the White House said that the United States is immediately reviewing its support for the Saudi-led coalition that has been bombing Yemen for the past 18 months. On Monday, the British Government asked to take part in Saudi Arabia's own investigation into the funeral attack.
This is a totally inadequate response to what should be far beyond the last straw in ending the UK's arms sales that are helping to fuel this brutal conflict. Michael Fallon, the Minister of Defence, has said that the UK would review those sales if the investigation finds that civilians were deliberately targeted. That pushes into the long grass a decision for which there has been ample evidence that the Saudi Arabia has breached the rules of war for more than a year.
Over 3,980 civilians have been killed since Yemen's current conflict begun in March 2015. According to the UN, Saudi-led airstrikes have killed the majority, though all sides have paid scant attention to saving civilians from the horrors of this bloody and seemingly endless war. More than three million people have been forced from their homes. More than 14million are hungry. More than 21 million people rely on humanitarian aid, more people than in any other country in the world.
Britain's role has never been logical - with one part of government funding vital humanitarian aid, while another part licences lethal weapons. This despite 18 months of mounting evidence that these same weapons are highly likely to be used to kill civilians.
The recent review by a group of Parliamentary Committees of UK arms sales to Yemen ended in a bad tempered public spat and splits largely along party lines, further giving the impression that the government is putting trade and jobs in the armaments industry above human rights.
More than £3billion worth of British arms, including bombs and missiles, were licensed for Saudi Arabia in the first year of the conflict. Last December the eminent QC, Philippe Sands, gave a legal opinion that such arms sales were in violation of both the UK's own legislation, and of the international Arms Trade Treaty which was incorporated into British law in 2015.
That law makes it abundantly clear that the UK Government should not licence arms supplies where there is a clear risk that they could be used to violate international humanitarian law, which requires every party to distinguish between civilians and combatants, something which Saudi Arabia, its allies and its opponents are patently failing to do. It is a conflict that has put Britain's aspiration to be a force for good in the world on the line.
As Ban Ki-moon, the UN Secretary General, has said, Saturday's slaughter of funeral-goers was an outrageous violation of humanitarian law. But it was not the first in Yemen's terrible war. Unless the UK and others stop fuelling the conflict with more arms, it will not be the last.
I imagine that Yemen is not often at the top of senior Ministers' agenda - it is a conflict where thousands die, millions go hungry, but perhaps overshadowed by the daily toll of death and destruction in Aleppo, as well as all the other vital concerns on their minds. But it is also a conflict that tests whether Britain is as good as its word, whether it conscientiously implements its own laws and the international agreements that it signs onto.
Some may argue that if the UK stopped selling arms others will. That may be the case. And it was for this reason, amongst others, that for over a decade the UK spent a great deal of political and diplomatic effort to get a global agreement to regulate the international arms trade. The UN's Arms Trade Treaty came into force at the end of 2014 and the UK was one of the first countries to incorporate it into law.
For such a staunch supporter of the treaty to be one of its most high profile violators is a stain on the UK's international reputation. The next time it argues for others to stand by their obligations in respect of international treaties it may not get the respectful hearing it would wish.
When I was in Yemen in June, I saw the terrible human cost of its conflict, the lives lost, the homes and hospitals destroyed, the futures blighted. It is not too late to help bring this conflict to an end, and to send the strongest possible message that killing civilians will not be tolerated. To do that, Britain should not delay another day in halting the arms sales that are fuelling this bloodshed and put all its diplomatic effort behind finding a political solution.