A certain Scots performer, very fond of the drink decided to belt a heckler. Walked to the back of the room and hit the wrong bloke. He took him out for a drink the following lunchtime, to apologise. Got drunk again slipped over and knocked the bloke off his bar stool breaking the mans arm on the way down. Surprisingly he never sent him a Christmas Card that year.
Quite surprised to find myself on the above link for the Woodman Folk Club, can't remember saying it!
By the way the Nolan sisters (Yes them!!) have got a brother who works the clubs as a comedian. He's got the best put down I ever heard. After constant interruptions from an unfunny Heckler, he paused and related the following story.

" Do you know I was bought up upon a farm, I was driving a tractor when I was eight. One day I managed to drive over my Grand mothers prize pig! She was furious, she said 'You've done a terrible thing son! That pig will haunt you for the rest of your life'
(Turning to the Heckler)... 'Well she was right! Look it's bloody well here!"