More than a million private renters across England have suffered at the hands of law-breaking landlords over the last year, according to estimates from Shelter.
Around one in eight (12.9%) renters have experienced problems ranging from landlords entering homes without permission and deposits not being properly protected to renters being abused, threatened or harassed by landlords or feeling they were unfairly treated due to their race, nationality, gender or sexual orientation.
The housing charity warned that "a minority of rogue landlords" are causing misery to renters by committing civil and criminal offences.
It said renters often do not know what their rights are. In the last year, Shelter's website has had more than 220,000 unique visits to its advice pages for people facing problems with a private landlord.
The research among more than 3,200 renters by YouGov estimated that, in the last 12 months, 64,000 renters across England have had landlords cut off utilities without their consent, and nearly 50,000 have had their belongings thrown out of their home and the locks changed.
Over 600,000 renters have had their home entered by a landlord without permission or notice being given, more than 200,000 have been abused, threatened or harassed by a landlord, and more than 110,000 felt they had been treated unfairly due to their race, nationality, gender or sexual orientation, the research estimated.
Shelter's helpline adviser Danielle Goodwin said: "Every day at Shelter we speak to people at the end of their tether after a law-breaking landlord has caused chaos in their lives.
"These range from instances where the renter has been unaware of their rights, to cases where renters are exploited and subjected to terrible experiences by a minority of law-breaking landlords."
David Cox, managing director of the Association of Residential Letting Agents (Arla), said: "These are very worrying statistics indeed, but they don't echo sentiment from our members.
"There is a minority of rogue operators in the sector and Arla continues to campaign for much greater regulation of the industry, and better enforcement against those who bring the sector into disrepute."
He continued: "It is essential that if we are to eliminate these criminal operators, the prospect of fines and enforcement must be seen as an actual deterrent, rather than merely a cost of doing business."
Richard Lambert, chief executive officer at the National Landlords Association (NLA), said: "These figures highlight serious issues that are simply unacceptable but our research with tenants shows that 82% say they are happy with their current landlord. Furthermore, Shelter's figures show the vast majority of landlords to be law abiding."
Mr Lambert said "it's not just a one-way street" and three in 10 landlords across the UK say they have been either verbally or physically abused by a tenant.
He continued: "What's important is that anyone who is harassed, abused or subject to what they believe to be illegal behaviour seeks immediate advice and reports the matter to the police and relevant authorities."
A Department for Communities and Local Government (DCLG) spokesman said: "We're cracking down on rogue landlords with over 40,000 properties inspected and more than 3,000 landlords facing further enforcement action or prosecution.
"We're also introducing banning orders, fines and blacklists and councils have been given £12 million to specifically tackle this issue."