It was at the end of a two day trip to Nigeria which had proceeded smoothly; we were there at the invitation of the Gates team, the only press to be attached to the entourage, and we had been given generous access to Mr Gates himself and entry to many of his engagements. It was a trip entirely devoted to his efforts to help eradicate polio from the country.
The interview went to plan until the end, when time was running short and I asked Mr Gates a couple of questions about his view of China and its censorship of the internet. He was clearly annoyed by the questions. They were asked in a cheeky and challenging tone, and they were right off the subject of the day.
His aide intervened (you could just hear that) and although the interview did carry on, the mood in the room was far less congenial than it had been.
It's worth asking what happened, both to help understand this particular case and how these kinds of things work in general.
This is one of those cases where there had been some advance discussion about the interview and its scope. That is often the case, but by no means always.
In this case, I think both sides would acknowledge that it had been agreed there would be a substantial interview with Mr Gates, and that it would include questions -but not a majority of questions - that went well beyond polio or philanthropy.
I think both sides would also agree that we had suggested various subjects that might come up (such as Microsoft and its relationship to Apple) but at no point had any warning been given about questions on China.
There is then room for a disagreement about whether it was reasonable to ask impertinent questions on that unannounced topic.
I think I can summarise the view of the Gates team fairly: they saw the questions as at best discourteous and at worst as a trap, an attempt to spring a surprise on someone who was unprepared. Either way, it is not right for broadcasters to behave that way.
To us, the China issue seemed like an interesting and reasonable one to raise, and within the agreed rules that the interview would range beyond Gates Foundation concerns. At no point had we said we would not ask about China.
Now, it is not normal for us to spell out in advance specific difficult questions that we wish to ask. For me, the main principle for broadcasters has to be that if people stand to benefit from an interview, they should be prepared to face some downside as well. That's why it would be wrong for interviewees to choose their questions and why it would be wrong for interviewees to choose what is broadcast (or to veto broadcast by allowing staff to break an uncomfortable interview up.)
If we agree not to surprise people with occasional difficult questions, the public will get an entirely skewed view of things, with a self-selecting sample of easy interviews.
Some would say we should never agree to terms and conditions: that we should not even have conceded that most of the interview would focus on Gates Foundation and related development issues.
I disagree. I think that condition was not one that would have constrained us much on a trip to Nigeria. What we should never concede are unreasonable terms. And I think we should do our best to be transparent about conditions that have been imposed where they do constrain us.
Indeed, in my view, it would have been quite reasonable for the Gates team to specify "no questions other than those relevant to Nigeria". But if they had done so it is highly unlikely that we would have taken up the invitation to go. One of our motives in going was to get up-close and personal with one of the richest men in the world.
The issue in this case is really whether the interview was within the agreed rules or norms. I think it was. Others can take a different view.
It might in fact be a simple matter of culture clash. For Gates, it seemed beyond the pale. For UK broadcasters (who are perhaps more feisty than their US counterparts), it just seemed like an ordinary day's work.