Yorkshire-born medium Stephen Holbrook snapped after enduring 40 minutes of abuse from a drunken man.
The heckler shouted "pile of ****ing s****" and as Mr Holbrook told a tearful woman that October 31 was an important anniversary for her and her late husband the heckler bawled out "halloween!".
At the end of the show Mr Holbrook punched the heckler on his head after he approached and started another torrent of abuse. A short scuffle broke out when the heckler retaliated.
Police were called to the Blackburn venue and Mr Holbrook was arrested and cautioned. Last night the ex-hairdresser, 39, who lives in Wakefield, said he was embarrassed to be arrested but the man had deserved it.
"He was verbally abusive, drunk and threatening. I was giving a lady a message from her husband. It was a sensitive moment. I told her a date and she said it was their anniversary. At that point I heard 'halloween' being shouted. It was embarrassing and the crowd were groaning at him. The man ruined it.
"There were people in the audience in tears as they received messages from loved ones and he kept interrupting with disrespectful remarks."
During the show, the heckler was up and down from his seat and left the room in search of more drink, he said.
Mr Holbrook, who has been described as Britain's most accurate medium, said: "I am not a violent man, but it's very difficult when you see someone causing so much distress to people going through an emotional experience."
He said the heckler was not hurt.