Andrew Feinstein is known in South Africa for his decision to resign his parliamentary mandate in 2001 to protest the refusal of his party, the ruling African National Congress (ANC), to allow an inquiry into a suspicious multibillion-dollar arms deal. He chose to investigate the scandal himself and published the results in a book. It was followed by "The Shadow World," an investigation into the global arms trade, which has been turned into a feature length documentary.

DW: The United Nations have, on multiple occasions, accused the Saudi-led coalition of committing war crimes in Yemen. Yet the flow of weapons to Saudi Arabia continues unabated. Why?

Andrew Feinstein: Saudi Arabia sits on the biggest reserves of oil in the world and oil is incredibly important to the West. A close political alliance with Saudi Arabia has various political advantages in terms of the price of oil, the availability of oil supplies, et cetera. Saudi Arabia has — especially over the last 25 to 30 years — become a more and more important ally of Western governments in Middle Eastern politics generally and is — together with Israel — the go-to ally for Western governments. So to provide those two countries with arms and weapons makes sense.

Even when a Saudi dissident journalist is killed in the Saudi Consulate in Istanbul?

Saudi Arabia can do whatever it wants. They have a free pass. It's a country that perpetrates massive human rights abuses against its own people and actually beheads more people every year than ISIS, ISIL, al-Qaida and all its offshoots combined and propagates the most conservative form of Islam, known as Wahhabism.

Saudi Arabia has a very complex relationship with elements that are sometimes described as Islamist extremist groups: there seems to be a sort of agreement that these militant groups will not target the Saudi royal family, because it provides them with various types of support, primarily of a financial kind. There is unequivocal evidence that Saudi has and continues to support some of these groups against whom the West is engaged in a war on terror. This makes the nature of the West's relationship with Saudi Arabia extremely complex and sometimes difficult to understand.

When American weapons turn up in Yemen on the side of the Houthis, America will feign real concern. But it's so obvious to anyone who follows the arms trade how they get there. These are weapons that are sold to Saudi Arabia, which Riyadh then provides to Islamist groups it's allied with in Syria in the fight against the Assad regime. And some of the same groups are operating in Yemen, which is how they end up being used against the Saudi-led coalition. Many of the weapons are smuggled through Oman, which often acts as the sort of conduit of illegal weaponry.

How can you export to Saudi Arabia when it so obviously flies in the face of German arms export control regulations, European common position on arms exports and the international arms trade treaty? Because, sadly, the regulation is a voluntary exercise. That's the case in Germany, just as it is in the United Kingdom, in Spain, France or in Italy. And I think amongst the worst transgressors in this regard in Europe are the United Kingdom and Germany.

But German politicians often pride themselves in Germany's very restrictive arms export guidelines and regulations.

Germany has restrictive arms exports only when it suits Germany. When it suits it politically, it turns a blind eye to arms exports that it shouldn't be allowing through its own laws and international obligations — including sales to Saudi Arabia. So to take one example: Rheinmetall exports certain ordinance to Saudi Arabia and probably the United Arab Emirates as well. In order to do so, they set up a factory in Sardinia in Italy. The ordinance is exported to Saudi Arabia and is used in the air war in Yemen, which clearly violates all of Germany's exports regulations. So, when German authorities are confronted with this, they say they don't control those exports, but that they are rather controlled by the Italian authorities, who, in turn, say they have nothing to do with the exports, because it's a German company. This, in essence, is a way for the governments of Germany and Italy to ensure that their companies can export pretty much what they want to whomever they want.

And there are additional examples of this: Rheinmetall has a partnership with Denel, the South African state arms exporter. Why would they do that? Because South Africa's Arms Export Control Committee doesn't even meet anymore, it's completely nonexistent. So Rheinmetall and other German companies can export whatever they want to South Africa and they know full well that those materials can then be exported on to whoever the end customer is. German companies are doing this all over the world and the German government is very well aware of it.

Andrew Feinstein is a founding director of Corruption Watch. The nongovernmental organization investigates corruption to develop measures to combat corrupt behavior by corporations and governments.

The interview was conducted by Matthias von Hein.