Special Advisers (Spads) are neither politicians nor civil servants; instead, they inhabit a sort of twilight world between the two. They are bound by the 'Code Of Conduct For Special Advisers,' which states: "The employment of Special Advisers adds a political dimension to the advice available to ministers, and provides ministers with the direct advice of experts in their professional field, while reinforcing the political neutrality of the permanent civil service by distinguishing the source of political advice and support.
"Special Advisers are employed to help ministers on matters where the work of the Northern Ireland Administration and ministers' party responsibilities overlap and it would be inappropriate for permanent civil servants to become involved.
They are an additional resource for the minister, providing advice from a standpoint that is more politically committed and politically aware than would be available to a minister from the civil service."
The work they would be expected to carry out includes reviewing all papers going to the minister, ensuring that party political implications are recognised, advising on departmental issues (especially if they are specialist in some areas), preparing speculative policy papers, contributing to policy planning within the department, liaising with the minister's own party, liaising with outside interest groups, speech writing, representing the views of the minister to the media and taking part in policy reviews. Put bluntly, they can do more or less what their minister wants them to do - albeit within the limitations of the Code Of Conduct.
All of which means that they have enormous influence. One former Spad told me: "When I attended and spoke at a meeting with civil servants, I spoke with the authority of the minister. Everyone in the room accepted that fact. I was his eyes and ears. If I was asked to meet people on his behalf then, again, they knew that I came with his authority.
"I briefed with his authority. I advised with his authority. I was often the person they would have to make contact with if they wanted to meet the minister in person. And yes, in terms of arranging meetings, or getting specific information to him, they needed to get past me first."
Another former adviser said that a key part of his job was ensuring that "MLAs and other elected representatives from his party were kept briefed about what the minister was doing in terms of policy. Some of them were always panicking that 'difficult decisions' - by which they meant anything that could have a negative impact on their constituency - would cost them their seats, so I had to assuage their fears or, at the very least, arm them with the reasons why the decision was necessary and unavoidable."
He also confirmed that it was normal practice for Spads from different departments to have what he described as "corridor conversations" on issues which required input from more than one department: "I had very good relationships with Spads from all of the other parties and we trusted each other to report back to our respective bosses accurately and quickly. Most of us would also build up a good relationship with key officials in our department, because it was important that everyone was kept in the loop."
In his interview with Stephen Nolan, former minister Jonathan Bell suggested that Spads outside his own department were instrumental in opposing his will on the early closing of the RHI scheme. I asked both former Spads if they would have had the power to do that when they were in their posts. Both said no, one adding, "Had I tried to muscle in on another minister's territory, I'm pretty sure I would have been told where to go. My own minister would certainly have told any other Spad where to go; and if he had found out that I was somehow working behind his back with other Spads I would have been sacked."
The other did say, though, that it was, "Not unusual for Spads from ministers in the same party to have 'corridor conversations' on some difficult issues - but those would have been done with the knowledge of our respective ministers."
I asked them if Spads working directly for the First Minister and acting on that authority would have the power, as Bell seems to be suggesting, to thwart the will of an individual minister?
Surprisingly, perhaps, neither of them ruled out that possibility, yet both said it would be a "provocative action" and would certainly be interpreted as such by any minister. If Bell is right, then it would mean that some Spads - those closest to the leadership - had powers not available to "mere departmental Spads."
But since there is no evidence, even in the interview, that Bell took the issue up with Peter Robinson at the time, it's an issue which will only be clarified by questioning the Spads concerned.
Generally speaking, Spads are an important part of the government/political process and many of them do good work; a fact that senior departmental officials acknowledge. But the terms and conditions of their employment are set out in their Code Of Conduct, which makes it clear that they are there to assist their ministers rather than work against them - let alone work against other ministers.
The First Minister denies Bell's accusations. He stands by them. One thing is clear, though, Spads are not capable of solo runs. Their influence and authority stems from their employer. One other thing is clear, too: by the virtue of the fact that they work for the First Minister it would be natural to assume that the Spads employed there might possess an influence and authority in their own right.
Or, as one of the former Spads put it: "When some people get to that level they may be tempted to believe that they are bigger than mere ministers, bigger than MLAs, bigger than the party and bigger than the structures. Bigger than the actual role they occupy."
Spads are now a part of the political process across the UK. They perform a role which cannot be undertaken by the civil service, while briefing their minister about broader party political ramifications. They are not expected to be politically neutral. But nor should they be encouraged to believe that they are more important than elected, fully accountable politicians.