It was bred in the USA by Mark Whitacre and was featured in many television shows as an exotic pet. In the 1980s it traveled all around the world to be kept in animal shelters. Then it was listed as a rare breed and its breeding was brought to Britain where it is now classified as an extinct breed. There are very few left in the country, but those who have kept them have described them as having a mean nature and being highly aggressive.
GWTM is said to be a purebred American mastiff and not a true Mastiff, as they are a smaller breed than American Mastiffs. The writer of a book called “The Great Britain Mastiff” claimed that it should not be classed as a mastiff. They have a long back and flat-coat but are otherwise very similar to the Bullmastiffs of the USA. Their history has been that of the more famous Barbet, the French Perrodes, and the English Fox Terrier.
There are several characteristics of the GW TM that are important to note. Firstly it has a short, sturdy coat that covers much of the body. It has a thick undercoat and stays white with age. Its skullcap is rounded and it does not have the prominent collar that the American Mastiff has.