Presenter Simon Mayo apologised to his BBC Radio 5 Live listeners after two guests swore while referring to far-right Dutch politician Geert Wilders.
The outburst happened yesterday afternoon, when a book discussion cut to a live interview with Mr Wilders, who was sent back to the Netherlands after being detained at Heathrow.
Mayo said sorry to listeners for the interruption - and Scottish detective novelist Quintin Jardine said it was fine as "w*****s like him need to be given airtime so that people can hear what they are".
There was an immediate apology from Mayo to listeners - but then American writer Dennis Lehane interjected, saying "W***** is such a great word".
Veteran broadcaster Mayo responded: "It might be a great word in America, we can't use it, it's not an appropriate word and we apologise for it."
The BBC received only one complaint over the incident.
Wilders, who is facing prosecution in Holland for inciting hatred against Muslims, had been invited by a British peer to show his anti-Islam film Fitna, which criticises the Koran as a "fascist book", in the House of Lords.
A BBC spokesman said: "During a live programme, two guests used inappropriate language which presenter Simon Mayo immediately apologised for. We are sorry for any offence caused."
Last week BBC Breakfast apologised after a technical error led to an "un-bleeped" extract from Christian Bale's expletive-laden rant being broadcast just before 7am.
Bale's outburst on the set of the new Terminator movie has become a huge hit on the internet.