A lot of prospective owners rule themselves out of getting a dog at all on the assumption that a flat with no garden isn't a fair place to keep one. That's not quite right, and it means the wrong question is usually being asked. The real one isn't "is my flat big enough," it's "is this particular dog's energy and noise level a match for how I actually live."

Size is the least useful predictor

A large, genuinely low-energy breed can suit a flat better than a small, highly-strung one. A bigger dog that's content lying around most of the day takes up more floor space but asks for less from an owner than a small dog bred to be constantly busy. Choosing by size alone tends to get this backwards.

What actually predicts a good fit

Energy level, matched honestly against how much exercise you'll actually give, not how much you intend to in theory. Noise tendency: some breeds and individual dogs are considerably more vocal than others, which matters more in a building with shared walls than it would in a detached house. Independence versus velcro-ness: a dog that struggles badly with being left alone needs a very different daily routine than one that settles easily, and that's often more about the individual dog than the breed label on paper.

A few illustrative examples, not a checklist

Worth treating as examples of the pattern rather than a definitive list. Every breed has real variation between individual dogs, and any breed's specific needs are worth researching properly rather than taking a single label at face value. Greyhounds are a commonly cited surprise here: built as sprinters rather than endurance runners, plenty are genuinely content with a couple of good walks and a lot of sofa time in between, which doesn't match their size-based reputation at all. On the other end, several small terrier breeds carry far more energy and vocal instinct than their size suggests, and can be a harder flat fit than a much bigger, calmer dog.

What matters more than the breed decision

Exercise commitment, honestly assessed. A flat with no garden means every single toilet break and stretch of the legs is a proper trip out, not a door left open onto a lawn, worth being realistic about before choosing, not after.

Neighbours and noise, practically. Thin shared walls mean barking at the door or during the day is a bigger deal than it would be elsewhere, and worth thinking about training for this specifically if it's likely to be an issue.

The tenancy itself. None of this matters if the lease doesn't allow a dog at all, so worth reading what actually goes into renting with a dog in London before falling for a specific breed that then can't come home with you.

The honest version of this advice is less exciting than a tidy list of recommended breeds, but it holds up better: match energy and noise to your actual life, not your flat's square footage, and the size question mostly takes care of itself.