Police raids in crackdown on 'slum landlords'
31 August 2012 Last updated at 18:33 BST
Last February a BBC investigation discovered large numbers of people living in slum conditions in Britain.
Many of them were illegal immigrants sleeping in so-called 'sheds with beds' - illegal structures provided by unscrupulous landlords.
Ministers have launched a nationwide crackdown, vowing to tackle those who illegally house people in converted substandard outbuildings.
Chris Rogers reports.