The following is a copy of the official Patterdale Breed Standard, written by Brian Nuttall, Holmes Chappel, England. This standard is used for conformation judging by the PTCA, UKC, and ARBA.
A sturdy, tough, active little terrier not too big in the chest. As a working terrier it must be capable of squeezing through very small passages underground to follow its quarry. A big terrier can cut of its own air supply.
The dog measures between 11 and 15 inches at the withers.
The dog should present a compact, balanced image, with straight legs.
Head and muzzle should be strong and powerful. (Scars received while working quarry should not prejudice a dog's chances of winning a show.)
Ears should be of moderate size (not too big or too small), folded to the side of the cheek.
Strong teeth, level mouth. (Teeth broken or incisors lost while working should not prejudice a terrier's chances of winning a show.)
Of moderate length, strong and muscular (a strong neck helps as much as a strong jaw in killing vermin.)
Coat is smooth to broken-coated. Smooth coated dogs should have a dense coat (not fine like a whippet's.) A good coat is important to protect against the wet underground and brush.
Tail is set high, length in proportion to body, usually about 5 to 7 inches long.
While hunting, these terriers can become trapped in an underground passage. In this situation they must be dug out before suffocating or suffering death from exposure and shock. The tail is sometimes the only thing by which to pull a terrier out; extricating it after it has become wedged in an underground burrow.
Black, red, liver (with red nose), grizzle, black and tan, bronze. The great majority of this breed will produce black-colored terriers, but the odd terrier of all colors will come with white feet and chest. Some of the best working examples of this breed are marked in this way.
Males should have both testicles fully descended into the scrotum.Fault - monorchidism.