The temperament of the bullmastiff combines high spirits. reliability, activity, endurance and alertness.

General appearance:
The Bullmastiff is a powerfully built and symmetrical dog, showing great strength but not cumbersome.

Head and skull:
'The skull should be large and square when viewed from any angle, with fair wrinkle when interested, but not when in repose. The circumference of the skull may equal the height of the dog measured at the top of the shoulder; it should be broad, and deep with good cheeks. The muzzle short, the distance from the tip of the nose to the stop shall be approximately one third of the distance from the tip of nose to the centre of the occiput, broad under the eyes and nearly parallel in width to the end of the nose; blunt and cut off square, forming a right angle with the upper line of the face, and at the same time proportionate with the skull. Underjaw broad to the end. Nose broad with widely spreading nostrils when viewed from the front; flat not pointed or turned up in profile. Flews not pendulous, and not hanging below the level of the bottom of the lower jaw. Stop definite.

Eyes:
Dark or hazel, and of medium size, set aside the width of the muzzle with furrow between. Light. or yellow eyes a fault.

Ears:
V shaped, or folded back, set on wide and high, level with the occiput, giving a square appearance to the skull, which is most important. They should be small and deeper in colour than the body, and the point of the ear should be level with the eye when alert. Rose cars to be penalised.

Mouth:
Mouth to be level, slightly undershot allowed, but not preferred. Canine teeth large and set wide apart, other teeth strong, even and well placed. Irregularity of teeth is a fault

Neck:
Well arched, moderate length, very muscular and almost equal to the skull in circumference.

Forequarters:
Chest wide, deep, well set down between the forelegs, with deep brisket. Shoulders muscular, sloping and powerful, but not overloaded. Forelegs powerful and straight, well boned and set wide apart, presenting a straight front. Pasterns straight and strong.

Body:
Back short and straight, giving a compact carriage, but not so short as to interfere with activity. Roach and sway backs a fault.

Hindquarters:
Loins wide and muscular with fair depth of flanks. Hindlegs strong and muscular with well developed second thighs, denoting power and activity, but not cumbersome. Hocks moderately bent. Cow hocks a fault.

Feet:
Not large, with rounded toes, well arched (cat feet), pads hard. Splay feet a fault.

Tail:
Set high, strong at the root and tapering, reaching to the hocks, straight or curved, but not hound fashion. Crank tails a fault.

Coat:
Short and hard giving weather protection, lying flat to the body. A tendency to long, silky or woolly coats to be penalised.

Colour:
Any shade of brindle, fawn or red, but the colour to be pure and clear. A slight white marking on the chest is permissible but not desirable. Other white markings a fault. A dark muzzle is essential, toning off towards the eye, with dark markings around the eyes giving expression. Dark toenails desirable.

Weight and Size:
Dogs should be 25 to 27 inches at the shoulder and 110 to 130 pounds in weight. Bitches should be 24 to 26 inches at the shoulder, and 90 to 110 pounds in weight. It must be borne in mind that size must be proportionate with weight, and soundness and activity are most essential.

Gait:
The movement should indicate power and a sense of purpose. When moving straight, neither front nor hind legs should cross, or plait. The right front and left rear leg rising and falling at the same time. A firm backline unimpaired by the powerful thrust from the hindlegs should be maintained denoting a balanced and harmonious movement.