As someone who was behind the camera, briefing presenters and booking guests, it has been interesting to see the BBC’s coverage of current affairs and politics put under scrutiny.

Political broadcasts often operate with only a single day’s preparation: issues arise in the news, suitable guests are immediately pitched and briefs are drawn up for presenters. But during the past few years this process has become increasingly haphazard as the number of credible political voices diminished with every passing week. The main reason for this is, of course, the all-pervasive issue of Brexit.

Traditionally, Westminster voices in opposition are only too glad to comment on the misdeeds of the incumbent party. But Brexit, especially during Theresa May’s administration, cast a strange spell on party politics. To comment publicly on May’s deal was to implicitly reveal one’s attitude towards Brexit. Very few MPs could afford to alienate one half of the leave/remain divide and even if their constituency might have permitted it, their party whip might not.

The sectarian division of Brexit was taken at face value; and guests contributed to a culture of reinforcing this schism rather than trying to understand or interrogate it

As such, the task of the political producer – to drum up panels of relevant and interested politicians for public debate – became almost impossible. Broadly speaking, there were only two types of guests for producers to choose from: Brexiteer evangelists or slick and power-hungry London remainers. That the discussion surrounding Brexit should be conducted from these two extremes has become accepted as a sort of national truth, but it certainly doesn’t reflect the real make-up of parliament or the country.

A large portion of blame for this disappearing act falls at the feet of the politicians, who effectively empty-chaired themselves. But the BBC played its own anxiety-laden part in the confusion too.

Under the leadership of director general Tony Hall there has been a commendable focus on balanced viewpoints on all political shows. Gone are the days of all-male panels discussing a crisis at a female refugee detention centre. But the manner in which this diversification was put in place by production staff swiftly descended into farce. A whiteboard would be marked up with a clumsy grid system. The grid would revolve around a set of key identities such as “woman”, “northern” or “poc” (person of colour). These would then be cross-categorised with political stances such as “Brexiteer”, “Tory” or “progressive”. Our task would then be to ensure that any proposed panel contained a complete balance of all these attributes.

On daily programmes, where a different panel needed to be booked five days a week, these grid meetings often descended into the sort of charade that certain rightwing columnists dream about. One notable incident came when in order to find an “authentic” northern voice, all plausible interviewees who displayed any obvious erudition were vetoed. In their place, newspaper owner Danny Lockwood was slotted into the identity sudoku, as his tone was seen to more directly signal his real northern identity. Several producers thought fit to mention that said individual was, in fact, a reactionary whose past achievements include mocking the “Zorro” outfits worn by some Muslim women. But the grids didn’t have any disqualifying categories.

Ironically, the main beneficiary of this combination of a grid-based representation and self-imposed Brexit omertà was the European Research Group. High-profile or cabinet politicians can only be reached via power-hungry special advisers and professional press teams. The ERG, on the other hand, has no press agents at all and was very happy to provide the “leave” voice that the grid demands. The sheer number of times Mark Francois was booked over the last year boggles the mind.

There is an understandable nervousness about criticising these sorts of editorial practices since it might provide material for the reactionary commentariat who have no desire to see any diverse voices in journalism at all. But there is no easy way around the obvious complications caused by this approach. As the grid became the be-all and end-all of programming in some shows, all other ways of thinking about politics went out the window. The sectarian division of Brexit was taken at face value; and guests contributed to a culture of reinforcing this schism rather than trying to understand or interrogate it.

It should be noted that this open approach to booking guests does not apply to BBC hiring practices or indeed attitudes towards its own staff. The bulk of its news operations are still dominated by white Oxbridge-educated men of a certain age, and the treatment of young producers and researchers can be questionable at best. One female producer told me that when she reported rape threats shouted at her by far-right activists outside parliament, she was simply told it was “part of her job”.

And when we were able to cajole a bigger name on to a show – I’ve been told by several producers that they were instructed to use powers of flirtation more than of negotiation – there was always a boozy familiarity between presenters, writers and MPs that demonstrated the perils of establishment thinking. A handful of MPs, deeply entrenched in London’s literary and intellectual circles, treat the BBC like a university common room. By default these individuals are remainers. To continue booking them (drinking with them), the production staff must then secure the presence of their leave-voting, far-right opposition. Off-camera, a highly influential Westminster social circle revolves around trips to various holiday homes in continental Europe, where various MPs and the journalists who are supposed to report on them have long been playing just as hard as they work.

Work in British politics is hard – and has been doubly so over the last few years – so it is understandable that an embattled solidarity develops between the press and the objects of their scrutiny. Without those parties on the Mediterranean I’m sure that many stories and interviews wouldn’t have materialised. But it is hard to stomach the ceaseless talk of impartial, representative journalism when the content of our shows frequently depends on which London politician fancies a drink after work.

The ideas behind Hall’s diversity drive were worthwhile: first, it could be presented as a solution to the establishment liberalism that had so badly failed to predict the conditions that fuelled Brexit; at the same time, it was intended to address the historic imbalances of class and race that still mar so much modern political reporting. In the end Hall’s initiative was a solution to neither problem. While the BBC was busy failing to change its structures and work practices with whiteboards, the most complex and unorthodox period of politics in a generation simply blew past – despite the considerable airtime given to it – the one group of people who were most trusted to shine a light on it.

• The author is a journalist who has worked for the BBC. This is an edited version of an article originally published in The Fence