A dawn raid found 17 young men crammed into a filthy three-bed house in north west London as part of a clampdown on rogue landlords.
At the overcrowded property in Kingsbury, Brent Council found exposed electrical cables amid general disrepair.
Tiny rooms had up to five beds in them, with grimy mattresses, next to a dirty kitchen and a leaking sink.
The backyard was also full of household rubbish and old mattresses.
All the tenants were young men, paying cash in hand to one person living in the property who then passed on the official rent of £1200 per month.
The total rent collected each month by the head tenant who now faces the prospect of prosecution proceedings was found to be £3,400.
Having to live with 16 other people in these cramped conditions is unacceptable. We are talking about people's lives and no one deserves to spend theirs in a grimy, overcrowded house with no hot water or heating. While there are many good landlords in Brent who have licensed their properties, there's still a significant number who haven't, who are operating illegally and exploiting people for profit.
Both rent recipients have been advised to leave the property immediately or face an unlimited failure to licence fine.
There was also one arrest made during the raid - which took place last week - for a previous offence.