Or not even just Central London. There are loads and loads of 1 bed flats for say £3,000-£4,000 a month for 50sqm. Two bed flats are usually the same price.
Dp and I could afford these, but choose a 2 bed instead. Even if I was single, and I could afford to rent one of these. Why would I when you can get the exact same thing for say £2200?
I've seen identical flats in the same apartment block go for £600 a month more than another.
But more importantly, who can afford these flats? I work in finance and dp works for a US law firm, so we both are surrounded by people on £200k+ a year, and no one we know would even consider spaffing 3k on a tiny one bed. I'm not even talking shiny tower block flats