James O'Brien is Leading Britain's Conversation.
Why does it rain "cats and dogs"?
Name: James O'Brien, LBC studio
Answer: Back in the day, when we slept in houses with fewer rooms, the cats and dogs would sleep on the roof area, outside. If it was raining very heavily they would come under the roof, but only if it was pelting down.
Name: Sean, Gants Hill
Qualification: Estate agent
Answer: Sometimes the roof would become so slippery in the rain, the cats and dogs would slide down through the room and into a room of the house – this is where the phrase came from.