@Beautiful3
I think its a good idea. Its an alternative from a house share. I would much rather live alone in a tiny bedsit, than share with others in a bigger space. Don't forget London is an expensive place to live, and that price includes utilities.
Yes. I've lived in far worse in London, I must say, and I can entirely see the appeal, if you want to trade off privacy for more space in a house share.
I also remember the old, unregulated bedsits that were common a few decades ago, which were often a bedroom-cum-kitchen where you could sit up in bed and fry and egg, and a shared, often gross, bathroom. My aunt was living in one in the 80s where her cooker was out on the landing because it wouldn't fit inside the room.
I also lived briefly in a student flat in Prague that had a shower cubicle in the middle of the kitchen. And a Kilburn squat where you regularly had to use an umbrella indoors.
Like @Herja, I know people who raise children successfully in very small spaces.