Why the pairing usually works
British Shorthairs are among the more reliable cat breeds for a dog-owning home, and temperament is the reason. This is a confident, placid cat that tends to assess a dog, decide it is tolerable, and carry on with the serious business of the day. Unlike nervous breeds that bolt at a dog's approach and trigger a chase, or confrontational cats that swat first and escalate, a settled British Shorthair usually holds her ground calmly or removes herself with dignity. That steadiness matters more than friendliness: most successful cat-and-dog households are built on mutual indifference that warms slowly into companionship, and this breed is very good at the indifference stage.
The dog decides more than the breed does
Honesty requires shifting the focus: whether a British Shorthair lives well with a dog depends mostly on the dog. A steady, cat-experienced dog who can lie down, look away, and be called off a distraction will be accepted by most British Shorthairs in time. A young, boisterous dog who lunges on the lead at cats outside, a terrier with an intense chase instinct, or any dog with a history of grabbing smaller animals is asking a great deal of even the calmest cat. If you are choosing a dog to join a British Shorthair, favour breed types and individual dogs known for low prey drive and trainability, and be wary of assuming that a dog who ignores cats at a distance will be equally relaxed at feeding time in a kitchen.
Introducing them without a first disaster
Keep the first week separate. Let the cat and dog smell each other under a door and on swapped bedding, feed them on either side of a barrier, and allow the dog to watch the cat through a gate or glass door while being rewarded for calm, disinterested behaviour. First meetings in the same room should be with the dog on a lead, the cat entirely free to leave, and sessions kept short enough to end on a bored note from both animals. Never carry the cat to the dog or let the dog corner her for a sniff; a British Shorthair who cannot escape will defend herself, and one early fight can set the relationship back months.
Designing the house for two species
Give the cat a dog-free geography. High, wide perches a solid British Shorthair can actually reach, a room or landing behind a gate the cat can slip through and the dog cannot, and feeding stations and litter trays the dog cannot access all prevent the daily small frictions that sour mixed homes. Dogs scavenging cat food and raiding litter trays cause more household conflict than temperament does. Also protect the cat's rest: a dog who is allowed to pester a sleeping British Shorthair for play will eventually be corrected by the cat, and the resulting scratch on a nose is a management failure, not a surprise.
What success looks like over time
Expect a slow arc. Sharing a room without tension, the dog walking past the cat's chair without either reacting, and the cat choosing to sleep within sight of the dog are the milestones of the first months. Some pairs go further: mutual grooming, shared sun spots, and the cat actively seeking the dog's company are all reported often with this breed, but they are a bonus, not a requirement. Sudden changes, such as a previously tolerant cat hiding, refusing to cross rooms the dog uses, or toileting away from her tray, deserve investigation; check first for a management change, then arrange a veterinary visit if the behaviour persists, because pain makes any cat less tolerant.
KinsLe Messenger gives that mixed household a single thread tied to her name, so a note from the dog walker, a question from family, or an update from a sitter lands in one place instead of scattering across everyone's phones.