THE UK Government is continuing to deliver deadly smart bombs with Scottish-made guidance systems to Saudi Arabia despite civil servants warning that they could not be sure their use in Yemen complies with international law.

The Paveway 1V bombs are made by US arms manufacturer Raytheon with the sophisticated guidance and targeting system fitted in its Glenrothes factory. They have been used extensively by coalition forces, led by Saudi Arabia, in the civil war in Yemen – including the airstrike on a funeral in the capital Sana’a in October in which 140 people were killed and hundreds more were injured.

Despite this, days later in early November, Foreign Secretary Boris Johnson pressed fellow cabinet member Liam Fox, responsible for international trade, to continue supplying the weapons. Johnson claimed that the Saudis had given commitments about the use of British-supplied weaponry which meant that “the ‘clear risk’ threshold… had not yet been reached.”

And although the United States had recently blocked the sale of precision-guided munitions, British sales continued.

Saudi Arabia is Britain’s most important weapons client, with sales of more than £3.3 billion since March 2015. Documents at the heart of a judicial review brought by the Campaign Against the Arms Trade (CAAT) demonstrate the level of uneasiness civil servants felt over the sales.

Johnson’s intervention to Fox came directly after Edward Bell, the Government’s top export official, wrote to him asking whether there was a clear risk of the supplied weapons breaching international humanitarian law. Earlier in the year he had advised the-then business secretary Sajid Javid that “my gut tells me we should suspend”.

On February 4 last year the head of policy at the Export Control Organisation, Christopher Chew, wrote to Javid expressing his concerns about the Saudis and whether the use of the British ordnance, which had killed civilians, might breach international law. Three weeks later a Paveway bomb hit a market in Sana'a, killing 40 and wounding dozens more.

In diplomatic language, Chew queried the decision to continue supplying armaments to the Saudis. He pointed out that the Ministry of Defence had been tracking 114 incidents of “potential IHL concern [international humanitarian law]" and that “only a very small percentage of the overall coalition airstrikes have been tracked”.

Saudi Arabia is notionally meant to inform the UK of forthcoming attacks with British bombs, but Chew makes it clear that the system is deeply flawed. He continues, in the official document marked ‘sensitive’, to say that while the Foreign Office ¬ then under Philip Hammond – is confident of their ability to make proper assessments, “we do have concerns regarding the gaps in knowledge about Saudi targeting processes and about the military objectives of some of the strikes.”

He added that in the incidents the MoD had been tracking, they “are able to identify a ‘valid military target’ for the majority of them. Additionally they cannot be certain that the vast majority of the total airstrikes that are not being tracked have all been IHL-compliant”.

He also expressed the department’s concern that the MoD “have very little insight into so-called ‘dynamic strikes’, where the pilot in the cockpit decides when to despatch munitions – which account for a significant proportion of the air strikes.”

Under UK export rules, licences should not be approved for sales if there is a clear risk that the weapons could be used for serious violations of international humanitarian law.

The international trade ministry will not comment on the proceedings, which concluded in the High Court in London last week, saying only that Britain operates “one of the most robust export control regimes in the world and we keep our defence exports to Saudi Arabia under careful and continual review.”

A judgment in the judicial review is expected in March. A spokesman for CAAT said that they too would be unable to comment until the verdict is reached.