Gallacher said: “Nigel Owens and I met at Stradey Park at 4.15pm and felt fog would have made the game unsafe. Not all of the pitch was visible and it wasn’t possible to determine whether it was going to get better or worse.
“We had to make a decision as we didn’t want the Newport Gwent Dragons and their fans to make a wasted journey.
“It’s obviously very disappointing as we were hoping for a good crowd for our first Welsh derby of the festive season.”
