Between 12 and 15 September, military delegates and government officials from all around the world will gather in London’s Excel Centre for the DSEI Arms Fair. While there, they will have the chance to buy weapons, many of which could be used to repress their own populations and attack other countries.

Although the 2017 guest list has not yet been released, countries like Saudi Arabia, Israel, Bahrain and Pakistan are among those that have been regularly invited to past events.

British politicians and military will also be out in force to greet our government’s invited guests and to try and talk them into buying weapons from UK-based companies. But why is the British government and military so keen to help private arms companies make profits?

One possible reason is that these companies often offer well-paid jobs to retiring ministers and military figures, who are therefore keen to help their potential future employers.

The boundary between the military and arms company, public and private, buyer and seller, is not as well-defined and well-policed as you might expect. Just looking at through the list of individuals speaking at DSEI makes this clear. Of the 38 arms company representatives scheduled to give talks at the arms fair, exactly half of them used to work for the military. This is the revolving door on steroids.

On Tuesday 12 September, for example, delegates will hear from George Zambellas, who will be speaking on behalf of a company called Liquid Robotics, which makes unmanned boats and is owned by US arms giant Boeing. Yet, while now in the private sector, when Zambellas attended the last DSEI Arms Fair in 2015, he was on the other side of the revolving door – giving a keynote speech as Admiral Sir George Zambellas, First Sea Lord and Chief of Staff of the Royal Navy.

In that role, Zambellas pursued policies which benefited companies like Liquid Robotics, his new employer. According to a Royal Navy blog post, the October 2016 ‘Unmanned Warrior’ exercise, which tested how robot boats could be used in the Navy, was the ‘brainchild’ of Zambellas. One of the companies involved in this exercise, was Liquid Robotics, who Zambellas joined in March 2017, just six months after leaving the Royal Navy and four months after the ‘Unmanned Warrior’ exercise.

Zambellas is one of many speakers to have taken a turn in the revolving door. It’s a similar story with Andrew Tyler, CEO of Northrop Grumman Europe. Tyler was previously the Chief Operating Officer for the MOD’s Defence Equipment and Support unit, which is in charge of buying and supporting all equipment and services which the Navy, Army and RAF need.

It’s not just military personnel and arms dealers speaking at DSEI though, it’s also government ministers – with no fewer than four scheduled to talk at the event: Defence Secretary Michael Fallon, Secretary of State for International Trade Liam Fox, Parliamentary Under Secretary of State at the Ministry of Defence Harriet Baldwin, and Minister of State for Security at the Home Office Ben Wallace.

They too may find themselves speaking to possible future employers: many ministers have gone through the revolving door to arms companies. These include Michael Portillo, John Patten, Roger Freeman, James Arbuthnot, Geoff Hoon and Ivor Caplin.

For Liam Fox, any future journey through the revolving door may be made easier by the fact that the man who was his special adviser as a minister until Fox resigned in disgrace following a lobbying scandal, Oliver Waghorn, is now BAE Systems’ chief lobbyist. Waghorn was hired by BAE Systems as ‘head of government relations’ in October 2016, just three months after Fox became Secretary of State for International Trade – the department in charge of promoting British arms exports and organising arms fairs.

Despite the risks of conflicts of interest, regulation of the revolving door in Britain is negligible. To go from the public to private sector, all that senior public servants have to do is apply to a body called the Advisory Committee on Business Appointments. In its 42-year history, this committee has never said publicly that an appointment is unsuitable.

However, the issue is far bigger than the professional choices of a few individuals. It is systemic. Research from The Guardian found senior military officers and MoD officials had received approval for over 3,500 jobs in arms companies just for the period from 1996 to 2012. Furthermore, arms companies regularly have staff seconded to the same government departments that are responsible for buying and selling their wares.

The impact of the close and insidious relationship between the corridors of Westminster and the upper echelons of industry isn’t just to help former politicians and civil servants to secure their next jobs, it’s also to influence and distort British foreign policy.

Former Foreign Secretary Robin Cook characterised well BAE’s influence over Whitehall when he said ‘the chairman of BAE appeared to have the key to the garden door to No 10.’ He added that he ‘never knew No 10 to come up with any decision that would be incommoding to BAE.’

The personnel may have changed since then, but events like DSEI show that the relationship is the same. This cozy partnership goes some way to explaining why, despite opposition from the vast majority of the British public, the government continues to arm and support human rights abusers and dictatorships like Saudi Arabia. If you want to get a good idea of the reasons why the government arms these regimes, then the champagne bars of DSEI are the first place you should look.

Joe Lo is a spokesperson for Campaign Against Arms Trade (CAAT). You can follow CAAT at @CAATuk.

The top photo shows an ad against DSEI 2015 placed in the London underground by CAAT. Photo via CAAT's Flickr account.