In the middle of the night, says Maria, groups of people can sometimes be seen moving into houses in her neighbourhood, far more than would seem to fit comfortably in the Victorian terraced homes.
Each of these houses has 10 to 15 people living inside, she estimates. Maria, an architect, suspects they are being illegally rented. "They're everywhere," she says.
Maria contacted Your Voice, Your BBC News after spending years complaining about these homes to her local authority in east London, Newham Council. We began investigating - and found a widespread black-market rental sector where people are forced to live in unsafe spaces.
Photos, videos and testimony from the people living in several properties like these showed unsanitary and overcrowded homes, with adults sleeping on bare mattresses in bunk beds, contending with black mould, rats and, in some cases, conditions that proved to be deadly.
Laws across the UK say large house-shares - officially known as houses in multiple occupation (HMOs) - must have a licence, so local councils can ensure each property is suitable for the number of occupants and meets gas, electrical and fire safety requirements.
