Iraq, Gilligan and Hutton. Three words etched on the consciousness of all BBC journalists. And - frankly - something I find difficult to talk about.
OK, it was the most damaging political row the BBC has ever faced. Editorial systems were criticised as defective.
It hurt but we fixed it. So why open old wounds by going over it again in front of an audience of students?
Quite simply, because we need to pass on what we learnt the hard way. We have a duty to tell each new generation of journalists what went wrong and why.
Journalism and humility don't go well together, but there comes a time when we all have to swallow our pride and today it was my turn to spend an hour and-a-half with 27 students at Cardiff University doing just that.
In a nutshell, we went through the story of Iraqi weapons of mass destruction point by point, at each stage pausing to ask, 'what would you have done if you'd been there?' We covered a lot of ground: trust, impartiality, resisting pressure, using single anonymous sources.
What did they get out of the 90 minutes? Afterwards I had a chat to some of the students, including Jamie Thunder, and I asked them just that.
