Many terraced houses in London have been built with access to the back of the house by a side gate, or with small patio/terrace areas to the side of the house. In many instances, these spaces are not wide enough to be usable space (except for outdoor storage) and many people choose to have a side return extension. This can make the kitchen / dining area (which is normally located in the garden side of the house) more spacious and let more light in - in many cases, planning permission is no longer required for extensions like this. If possible, glass ceilings or skylights can have a big impact on the amount of natural light entering the space - giving the illusion of an even bigger area!