Johnners - Leg over
It’s called corpsing. You laugh; at the wrong moment. The more you try to stop laughing; the more you laugh. And then just as you recover, your mind drifts back to why you were laughing in the first place; and off you go again. If it’s in the middle of a supposedly serious piece; so much the better.
There's something about the laughter in a genuine corpse which is utterly infectious. And here’s one such example from 1991.
When commentating for BBC Radio 3’s Test Match Special at the Oval, Jonathan Agnew mischievously suggested that Ian Botham had failed to "get his leg over"; Brian Johnston responded. As the Radio Times would say, "with hilarious results".