The ORIGIN of the British Shorthair is – as the name suggest Britain – they developed from sturdy english street cats. At the earliest cats shows in England around 1870 there were 2 kinds of blue shorthair cats shown: the British and the Russian - the difference between the breeds were way more subtle than they are today. To widen the genetic basis they were also bred together, which made the differences even smaller, until 1899 they were registered as one breed "Shorthair blue". In France the blue cats - that go back to the 16th century - were called Chartreux. After the world war 2 very few breeding cats were left. To revive the breed stocky household pets and Persians were used to continue breeding - only the French chose another route, they bred them with Russian which soon led to a very different look. Finaly since 1977 the Chartreux and the British Shorthair were bred as seperate breeds. 1982 another seperation broke away the European Shorthair from the British Shorthair. The breeding practice after world war 2 reintroduced the longhair gene into the breed - that persisted over the times - until it finally was recognised as a second coat length variation of the British.
The APPERANCE of the British Shorthair is that of a stocky teddy bear. On a British everything should be round - the head, the eyes, small ears with rounded tips set well appart, wide chest, compact body on stzrdy legs. On shows you will often see cats that dont resemble that discription in all points. The resaon for that is, that the breed standard describes a fully mature male, females are often markedly slimmer in bulit. Also the British is a slow developing breed, they take 3-5 years to reach full maturity - the cats on shows are often younger than that. The British grow relatively fast to their full size (frame) but the substance - the width so to speak - as they are not fat but musculare developes slow. A special characteristic of the British is their short dense coat - so dense that it literaly stands away from the body. When it comes to colors blue is still the best known althogh British come in all colors! There are solid colors, bicolors (with white) as well as all variations of tabby and pointed and any combination thereof.
In PERSONALITY the range is nearly as big as in color - what always fits: A British is more active than a Persian and quieter than a Siamese/Oriental. Though the differences in personality between certain color groups are quiete evident. While the solid blues are often "very British" meaning they keep their distanced and reserved, the colorpoints are wy more attachted to people, talk more and are often also more outgoing towards strangers. British are the perfect indoor breed. In terms of grooming they can anage very well on their own - though a light support by grooming with a wide toothed comb is usually appreciated.
Here is the TICA British Breed Group Standard