When is a Mandela joke not a Mandela joke? Stop asking and just say you're sorry

Simon Amstell was on Radio One yesterday morning, and made a joke at the network's expense:

Amstell said: "What is going on? We're next to 1Xtra, it's so white in here. Mandela would not approve of the situation at the BBC."

When Nick Grimshaw asked why, the guest replied: "Look at all these people in here." Grimshaw answered: "There's a lot of people."

The comedian then said: "Yeah, but look at the segregation that's happened."

He then laughed when the producer of the Breakfast Show, Matt Fincham, said: "I don't think that's the right thing to be saying right now."

Amstell added: "Well, someone had to say it. Mandela would say it if he was here."

Apparently, this silly joke about how the BBC created a station for black music was offensive, somehow, so Amstell has been made to apologise:

"It may have been unclear this morning, as things often are but what came out of this mouth today was silly. Apologies to everyone involved."