Yes he did unfortunately.
It was actually going to be addressed in a scene during the episode but sadly it had to be cut for time - this is what I was told by the script producer:
Wowsers! I'm surprised they let that happen. I assumed when watching the scenes with Maureen that it would have somehow turned out that she wasn't actually Colleen's daughter.
Thanks for clearing it up for me
I'm really really sorry if this has been asked already, but I'm just watching an old episode, where Alf is sleeping with Coleen's daughter. I know that Coleen turns out to be Alf's sister! Was this ever explained? Did Alf really sleep with his niece?
We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.