Here is the whole exchange from yesterday's Midweek on Radio 4.
Howe: Since black offends Joan I will make it..
Rivers: Wait. Just stop right now, Black does not offend me. How dare you, how dare you say that. Black offends me? You know nothing about me, you sat down here. How dare you.
Howe: The use of the term black offends you.
Rivers: The use of the term black offends me? Where the hell are you coming from? You have got such a chip on your shoulder. How dare you say that to me.
Howe: I think this is a language problem.
Rivers: No I don't. I think this is a problem in your stupid head. You had a child, you left them, your wife said you weren't there. You married a woman, you deserted her, now your son comes back he's got problems. Where were you when he was growing up, until he was eight years old?
Howe: May we continue?
Rivers: How dare you. Please continue, but don't you dare call me that. Son of a bitch.
Purves: Right Darcus, can we just say you don't think Joan is a racist and then perhaps we can move on?
Howe: I don't know whether she is a racist or not. I don't care.
Rivers: You just said the word black offends me. That's the stupidest thing I ever heard.
Howe: Normally I wouldn't ever meet you in my life.
Rivers: No normally would I meet you, nor would I choose to meet you.
Howe: No she's not a racist.
Rivers: OK please continue about your stupid film.
Purves: Right can we talk about your tour Joan?
Rivers: Talk about anything you want.
Howe: I don't think you brought me here to be insulted.
Rivers: No I don't think I was brought here to be insulted by someone, to be called a racist.
Howe: Let's go on with my film please?
Rivers: Please go on with your film.
Purves: Well we have to move on for time reasons. (To photographer Andrea Jones) Andrea shall we talk about plant photography?