LBC presenter Iain Dale branded a caller a "blithering idiot" in one of the radio station's most heated exchanges.
A conversation with a caller named Nigel quickly turned sour when he accused Dale of sympathising with Palestinian group Hamas.
The pair had been discussing whether to negotiate with terrorists, in light of a government report suggesting Britain should be prepared for dialogue with "unsavoury" groups.
Dale, who lost an associate in the 1996 Docklands bombing by the Provisional IRA, denied the accusation and told the caller to "open your ears mate".
During the conversation, Dale and the caller argued over the distance between Docklands and Tower Bridge, where Dale had been during the attack.
As the conversation heated up, Dale could be heard telling the caller, who admitted trying to wind the presenter up, to "shut up".
Toward the end of the phone call, having noticed Dale's anger, the caller said: "You've lost your temper."
Dale responded: "Yes I have lost my temper with you because you’re a blithering idiot, that's why."
Despite this, several listeners congratulated Dale on Twitter for the way he handled the call.