There aren't many things that unite Labour governments, Conservative governments and coalition governments, but one of them has been a mutually fawning and back-scratching relationship with the regime in Riyadh.
For decades now, irrespective of which party or Prime Minister has held office, Downing Street has continued to arm and support what is unquestionably one of the most brutal, repressive and misogynistic dictatorships in the world.
At a time when questions are being asked about Saudi Arabia's links to the funding and promotion of terrorism, and when UK fighter jets and bombs are central to the humanitarian catastrophe Saudi forces have inflicted on Yemen, it is more important than ever that the toxic relationship comes to an end.
Saudi Arabia has been a political ally and major buyer of UK arms since the 1960s, with Whitehall and Downing Street taking a keen interest in maximising sales. Right from the start, the deals, which also included military training, have been complemented by an unbending political support.
The first real landmark deal came in 1985, when Margaret Thatcher helped to broker the major Al Yamamah' deal between BAE Systems and Saudi Arabia. At the time it was the biggest arms deals in UK history - reportedly helped by former BAE Chair, Dick Evans, ability to eat sheep's eyeball.
The deal, ironically a translation of 'the dove', saw Saudi Arabia committing to purchase an initial cost of £4 billion worth of military aircraft. It was followed three years later by an even bigger deal, 'Al Yamamah II', that included helicopters, minesweepers and an airbase. Both deals included long-term maintenance deals staffed by UK personnel.
The deals would subsequently become the subject of a Serious Fraud Office (SFO) investigation, following multiple accusations of corruption. The investigation, which began in 2004, was cancelled in 2006, following political pressure and an intervention by the then Prime Minister, Tony Blair.
Shortly after Blair intervened, and the investigation was shelved, Saudi Arabia agreed a new deal for 72 fighter jets, including many of the ones that are flying over Yemen at the time of writing. The deal was known as Al Salam; which, in a classic example of doublespeak, is a Saudi translation for peace.
David Cameron continued in the same vein, with regular visits taking place between London and Riyadh. Prince Charles was co-opted in 2014, dancing at a BAE-sponsored event in the Saudi capital, just 24 hours before the pricing of a major fighter jet sale was finalised.
In 2015, the Saudi military began its ongoing bombing campaign in Yemen. At the time, the then Foreign Secretary, Philip Hammond, made clear that they were doing so with the full support of the UK. "We'll support the Saudis in every practical way short of engaging in combat" he said.
He's stuck to his word, at present UK-trained Saudi forces are flying UK-made fighter jets and dropping UK-made bombs. The results have been devastating. Over 10,000 people have been killed and millions have been left in urgent need of medical attention. Yet the arms sales and the political support have continued.
The legality of the arms sales that have underpinned the terrible bombardment has been the subject of a landmark judicial review, which was heard in February, following an application by Campaign Against Arms Trade. The result is still pending.
Despite the backdrop of destruction, and the ongoing legal process, Theresa May visited Riyadh in April. While there she rubbed shoulders with Royalty and called for even closer relations. No doubt the main winners from an even closer political embrace will include the Saudi Royal Family, who will gain greater international respectability, as well as BAE Systems and other arms companies that have profited from every step of the shameful partnership.
One feature of the relationship has been the establishment of a permanent Saudi-funded UK civil-service presence. Around 240 UK Ministry of Defence civil servants and military personnel work in the UK and Saudi Arabia to support the contracts through the Ministry of Defence Saudi Armed Forces Programme and the Saudi Arabia National Guard Communications Project. This unique level of international infrastructure makes clear how ingrained the relationship is.
Over the last 40 years the Saudi regime has executed thousands of people, suppressed millions more, and have created a humanitarian catastrophe in Yemen. Serious questions are being asked about the regime's role in the funding of terrorism and violence. Yet, despite its long list of abuses, it has been supported every step of the way by Westminster.
Thankfully the issue has received a lot more scrutiny over recent months, with MPs from all parties, including the Conservatives, raising questions, and all major opposition parties uniting in calling for an end to arms sales.
Regardless of who wins the election, if the next government wants to help the people of Yemen and Saudi Arabia then it must put a stop to a relationship that has killed too many people and whitewashed too many atrocities.
Andrew Smith is a spokesperson for Campaign Against Arms Trade (CAAT). You can follow CAAT at @CAATuk.