I thought a little about it being a Halifax, but I didn’t think the engine nacelles looked right. IMHO, they’re too long and too skinny for a Halifax. To be honest, though, the image size and angle make it hard to tell. My money is on Lancaster, but it wouldn’t shock me to be find out it’s a Halifax.
(Just a quick test to see if the GoComics nannybot is bleeping my screen name, as it appears to have done in ironflange’s post. The next word should be my screen name: CoBass)