i have been reading with intrest all your comments on olde thyme bulldog threads now i know of a litter of cross bulldogs and i would be intrested in puppy but have been told that they might turn out to be nasty as they have been crossbred with a bullmastiff is this true thank you. Mary

No dog is born nasty, its all to do with firm and consistant training.

Bullmastiffs and Bulldogs are quite laid back dogs, I see no reason whatsoever why this cross could turn out to be nasty, what you have been told is wrong, dogs can turn nasty because of lack of understanding and training, or because of certain lines.  Look at the parentage of both the parents look for reputable well known lines of both the Sire and the Dam, ask if the Bullmastiff was hipscored if not walk away.

But please go through both the pedigrees of the Sire and the Dam.  And if you are not at all sure walk away :)