So what is the point of these five non-execs sitting on BBC board?

I couldn't name one. He laughed and said: "Neither can I. Perhaps you had better find out who they are and, while you're at, what the hell they do."

I was still thinking about that when I found myself in the company of a BBC trustee who was none too enamoured with the "know-nothing non-execs" who get a lot for "apparently doing nothing".

The use of "apparently" was an attempt at fairness but they had my attention. I asked around. Outside of media commentators, no journalist I spoke to even knew of the nonexecutives' existence, let alone their function. My question provoked more questions, of course, especially among those who, unlike me, are predisposed to think the worst of the BBC.

How much do they earn? Who had the bright idea of appointing them? What is their role? Are they fulfilling their remit? Is there any point? Is it another case of jobs for the boys? Haven't they got enough to do in their day jobs?

Here then is a guide to the five men - not three, Mr Ofcom - who were appointed to the BBC board a year ago as non-executive directors. The senior non-exec is Marcus Agius, chairman of Barclays, and the others are Mike Lynch, co-founder and chief executive of Autonomy Corporation, David Robbie, finance director of the packaging company Rexam, Robert Webb QC, general counsel at British Airways, and Samir Shah, chief executive of an independent broadcasting production company, Juniper, and a former head of political programmes and head of current affairs at the BBC.

The cunning wheeze to appoint these five emerged from the charter renewal negotiations and it is unclear whether the idea of having outsiders, or independents, scrutinising the BBC's executive operations came from within the Corporation or was imposed by the Government.

Their role is to act roughly as nonexecs do in public companies (without, of course, the same financial risks) by ensuring that the board is carrying out its duties properly. In the words of a BBC spokesman, they should be "critical friends" offering external judgments on decision-making from the basis of their outside experience. As members of the board they are completely separate from the Trust, which sets the overall strategic direction of the BBC and oversees the work of the board.

The structure does suggest why some trustees might not be enamoured with the non-execs, believing that there could be either a duplication of roles or, more pejoratively, no real role at all for the non-executives. However, I am assured that the non-execs, who between them chair several key committees - not least that involving remuneration - have played a full role in affairs over the course of the year.

For their trouble they are paid a basic £35,000 fee, though they also collect an extra £5,000 for chairing each committee and expenses. It has to be said that, given the income they enjoy elsewhere, it is obvious that they are not doing it for the money. "They do it," said an insider, "because they genuinely love the BBC."

In Shah's case, incidentally, there is a potential conflict of interest, because his company produces programmes for the BBC, but he steps out if the board touches on any area that might affect his business expertise in broadcasting is considered.

For example, Shah, along with Agius, advised Director-General Mark Thompson over the Crowngate affair which led to the departure of the BBC 1 controller Peter Fincham. Non-executives were also consulted on the various episodes of fakery that have shaken public confidence in the BBC's credibility.

I think it fair to say that the nonexecutives, unlike the Trust and unlike the executive board members, have not built any kind of public profile for themselves. Nor has their crucial work been subject to any questioning by MPs on the Culture, Media and Sport Select Committee. They have neither sought to be questioned nor been invited to do so. It is obviously not a case of secrecy. But they do need to publicise their work in order to overcome the perception that they are not actively involved.

There could be a sixth non-executive sometime soon. The post has remained unfilled since last December, and there is no requirement to appoint, but I understand one may well emerge.

So, Mr Ofcom, I wonder if this answers your questions. I also wonder whether your original question to me had something of a hidden agenda. Could our giant broadcasting regulator be desperate to assume total responsibility for overseeing the BBC regardless of its internal checks and balances?