How quickly things can change in the world of international diplomacy. Not least of course when you have Boris Johnson as a foreign secretary.

On Wednesday Prime Minister, Theresa May was rubbing shoulders with Saudi Arabia’s King Salman, and talking of a “vital partnership” and the UK’s desire to “strengthen” its relationship with Riyadh.

By Thursday, Britain’s senior diplomat, Johnson, was accusing the desert kingdom of “puppeteering” proxy wars in the Middle East.

That the PM was none to happy with her foreign secretary’s comments would be an understatement.

One colleague of Theresa May’s suggested she would need to be “peeled off the ceiling” in rage.

Many British diplomats past and present were astonished at the foreign secretary’s remarks.

“I've never seen the likes of it in my 40 years of diplomatic experience and therefore Boris is skating on thin ice,” said Peter Ford, former British ambassador to Syria, who added he believed Johnson had been handed “a warning” by the government over his remarks.

Today Boris Johnson finds himself in Saudi Arabia after delivering a keynote speech in Bahrain on Friday that was much more on message in terms of the UK’s relationship with the Gulf States.

“Any crisis in the Gulf is a crisis in Britain”, Johnson stressed to delegates at the regional conference at the Institute for Strategic Studies Manama Dialogue on the first leg of his tour of the Middle East.

The foreign secretary also used the speech to reassure the region of the opportunities the UK leaving the European Union will bring when it comes to Free Trade.

“Now is the time for my country to seize the opportunity of leaving the EU,” Johnson said.

“We’ll still be there to stick up for our friends and partners in the Gulf... (where) for the first time since the 1970s we will additionally be able to do free trade deals.”

While forever unpredictable, few diplomatic observers doubt that as long as he is in Saudi Arabia, Johnson will remain on message and toe the official line on UK-Saudi relations.

There will be yet more talk of strengthening ties and of UK support for Saudi Arabia’s controversial military involvement in the war it is waging in neighbouring Yemen.

Saudi Arabia has long been regarded as the UK’s closest ally in the Middle East. It is, in essence, a relationship build on oil and weapons.

The only country in the world named after a family, Saudi Arabia is the world’s petrol station and has been since the 1930s, when it came into being.

Critics of Britain’s links however point to a cosy and often shadowy connection with the House of Saud that also reveals the hypocrisy and double standards of UK foreign policy in the wider Gulf region.

Even among the Tory party’s own ranks the UK government’s ties with Saudi Arabia frequently rankles.

“To the proxy wars charge, I’d add beheadings, judicial mutilations, torture, violation of women's human rights through male guardianship, unfair trials, gross restrictions on free speech, rights of assembly and association, bombing civilians in Yemen,” observed Tory backbencher Sarah Wollaston, in response to the foreign secretary’s latest diplomatic gaffe.

Right now above all else it is Britain’s provision of weapons and military support for the Saudi-led war in Yemen that has courted the most controversy.

For over 18 months, UK fighter jets and UK bombs have been central to this military campaign that has led to the widespread destruction of the poorest country in the region.

In the prosecution of this war, schools, hospitals and homes have been destroyed in a bombing campaign that has created a humanitarian catastrophe.

It is estimated that 3,799 civilians have died since March 2015 and at least 7.6 million people, including three million women and children, are currently suffering from malnutrition. Some three million people have also been forced to flee their homes.

In August the UN Office of the High Commissioner for Human Rights (OHCHR), reported that airstrikes facilitated in part by British weapons and support had been the “single largest cause of casualties” over the past year.

Downing Street meanwhile has continued to stress its support for Saudi Arabia’s actions describing it as “a vital partner for the UK, particularly on counter-terrorism.”

UK officials have consistently pointed to how the sharing of intelligence has been a key pillar of the UK-Saudi relationship since the 9/11 attacks in the United States.

“When you look at what is happening in the region, we are supportive of the Saudi-led coalition which is working in support of the legitimate government in Yemen against Houthi rebels,” stressed a spokeswoman for No 10 responding to Johnson’s gaffe on Thursday.

The Saudi-led bombing with UK help has destroyed roads which combined with restrictions on imports has made it near impossible to get food into and across Yemen.

According to the UN, food imports have slumped from 613,630 metric tonnes in November 2015 to just under 240,000 metric tonnes in October this year. Around half of Yemen's 28 million people are “food insecure,” and seven million of them do not know where they will get their next meal.

Mark Goldring, the chief executive of Oxfam GB, summed up the views of many humanitarian workers recently saying that Yemen was being “slowly starved to death,” and the country’s ability to care for its people was on the “brink of collapse.”

The current humanitarian crisis is inextricably linked to the Saudi-led military campaign of which the UK is a staunch supporter.

Already two UK parliamentary committee reports have called for Britain to stop selling arms to Yemen until an independent UN led inquiry has issued its findings.

These pleas however have fallen on deaf ears within the UK government.

Boris Johnson, along with Defence Secretary Sir Michael Fallon, Priti Patel, the Development Secretary, and Liam Fox, the Trade Secretary, have all said that Britain will continue to sell weapons.

“The UK can’t wash its hands of what’s happening in Yemen - with our massive arms sales to Saudi Arabia we’re deeply implicated in the Saudi-led military coalition’s indiscriminate bombing of Yemeni homes, hospital and schools,” says Amnesty International UK’s arms control director, Oliver Sprague.

“Only this week both Theresa May and Boris Johnson have tried to justify the UK’s arming of Saudi Arabia. This is a disgrace.

“With such a clear and continuing risk that any British arms sold to Saudi Arabia could be used to commit breaches of international humanitarian law in Yemen, the UK should immediately suspend all such arms sales.”

Despite such political condemnation and mounting death toll, the arms exports continue unabated. Whitehall has licensed over £3.3bn worth of weapons since the intervention in Yemen began last March.

Right now the UK government is actively working with BAE Systems to secure the sale of a new generation of the same fighter jets to Saudi Arabia that are being used in the current bombing.

Saudi has long been regarded as a “priority market” for the UK defence industry - and the Al-Yamamah arms deal of the 1980s, in which Saudi Arabia initially bought Tornado and Hawk jets and latterly Typhoon fighters, was the largest in British history.

Even when criticisms of such deals are made they are often ignored or met with indifference.

One example is the most recent ‘Human Rights and Democracy‘ report from the UK Foreign & Commonwealth Office (FCO) in which Saudi Arabia is listed as a “country of concern.”

Human rights campaigners have long been aware of how things are done in a country based on an absolute monarchy and where local elections are a novelty and women are still officially banned from driving.

They have long known too that Saudi Arabia’s own sharia judicial system imposes harsh punishments, including beheadings, stoning, crucifixions and flogging on its own citizens. To protest against the regime is to risk your liberty, and even your life.

The case of Raif Badawi, a Saudi writer, dissident, activist and liberal blogger, who was flogged in public 50 times for exercising his right to free speech and is still languishing in prison, is the most recent and highly publicised case that attracted global condemnation.

While the recent FCO report highlights any number of human rights abuses taking place in Saudi Arabia it never makes any reference to the incompatibility of such a record with the UK’s licensing of £1.9 billion in military exports during the two years that preceded the report.

The simple indisputable fact, say rights campaigners, is that for decades UK leaders of all political colours have worked hand-in-glove with the Saudi authorities over arms deals and turned a blind eye to the country’s appalling record on human rights abuses.

“Over recent years we have seen Tony Blair intervening to stop an investigation into arms exports to Saudi and David Cameron flying out to Riyadh to meet with royalty," observed Andrew Smith a spokesman for Campaign Against Arms Trade (CAAT) recently.

“Last year saw the shocking but ultimately unsurprising revelation that UK civil servants had lobbied for Saudi Arabia to sit on the UN Human Rights Council, a move which would seem comically ironic if the consequences weren’t so serious.”

Keeping Saudi Arabia sweet has always been a UK government priority when the desert kingdom stands as the UK's largest trading partner in the Middle East. The figures speak for themselves with 200 joint ventures worth £11.5bn and some 30,000 UK nationals living and working in the kingdom. British exports there alone sit at £7bn, while Saudi Arabia is a major inward investor in the UK economy.

Against this backdrop, the Saudi regime has always understood the importance of muting criticism, and the international legitimacy that they get from UK support is just as powerful as any of the weapons they are buying.

But on the arms supply issue there are other very real concerns too. In its extensive report entitled: The Arabian Connection: The UK Arms Trade to Saudi Arabia, the group Campaign Against Arms Trade, point out that there is a great deal of evidence to suggest that Saudi Arabia is far from a reliable end-user of UK weapons.

It highlights how the kingdom has secretly funded rebel or resistance movements around the world, often at the behest of certain elements in the US Administration in return for arms packages. As with any arms deals there are also no guarantees that the weapons the UK has lavished on Saudi Arabia will not be turned against the UK itself.

In his book The Business of Death, Britain's Arms Trade at Home and Abroad, author Professor Neil Cooper, says that despite the lessons of the Gulf War and the Middle East Arms Control Initiative which followed it, the UK has continued to supply an already “arms-saturated” kingdom and such behaviour seems “more likely to diminish the UK’s military security in the long run than reinforce it.”

On Friday while speaking in Bahrain, Foreign Secretary Boris Johnson spoke of his “profound concern” for the people of Yemen. He was at pains to point out “force alone will not bring about a stable Yemen and that’s why we in London have been working so hard with all our partners to drive that political process forwards.”

If Johnson’s observations on Saudi Arabia upset the Prime Minister earlier in the week, then these latest remarks will have a distinctly hollow ring for those Yemeni citizens who are bearing the brunt of Saudi-led airstrikes.

As aid agency Oxfam flagged up earlier this year, this is a British government in “denial and disarray” over its arms trade dealings.

It’s hardly surprising then that it stands accused of crass hypocrisy.

This after all is the same British government rightly calling on Russian forces to stop bombing civilian areas in the Syrian city Aleppo. All the while though, it’s only too willing to arm and support Saudi Arabia as it unleashes devastation on Yemen.