This feature was due to the placement of fireplaces in the corner of two neighboring houses resulting in a shared chimney stack. These houses with their unique architecture at the time were common in Marrowbone Lane and the surrounding area, but many have since vanished or have been demolished.
The presence of fireplaces in the corners of neighboring houses led to a shared chimney stack, a characteristic found in many homes on Marrowbone Lane and nearby areas during that period. However, many of these unique dwellings have since been altered or destroyed.