4 bedroom flats are relatively unusual as most homes with 4 beds would occupy an entire house. That said, many of the new penthouse developments and luxury flats across the UK come equipped with 4 bedrooms (and typically 2-3 bathrooms). These won't be cheap though! The most expensive 4 bedroom flat advertised in the last 12 months was in London's Belgravia and was put on the market at an eye-watering £22m! Not all 4 bedroom flats are so pricey though many of the UK's ex-local authority buildings have 4 bedrooms and can be a serious bargain for young families or flat sharing students.