While many of the landlords only refused to let when contacted in person, some are more blatant in their bias against tenants on benefits. The Bureau analysed the text of some of the advertisements and found 80 that explicitly stated “No pets. No DSS [a slang term for benefits claimants]” or “no housing benefit”.

Jon Sparkes, the chief executive of Crisis, told the Bureau: “We should all have a safe and secure home. This investigation paints a clear picture that for the overwhelming majority, we're not meeting this basic human need. This is simply unacceptable – we can and must do better.”

Leilani Farha, the UN special rapporteur on the right to housing, responded to the Bureau's findings, saying: “What is clear is that there is a systematic disregard for the human rights of those most in need.

“It’s shocking that so many landlords would simply deny access to housing based on the applicant’s source of income. That’s blatant discrimination and is unacceptable.”

Refusal after refusal means that Ruth and her boys are living in a small caravan on a friend’s driveway. The family had to give up their pets when they moved in, and Ruth’s 11-year-old son, who has autism, is feeling the loss of his cats. They have been in the caravan for two months and Ruth is not sure what will come next. “I’m doing what the council tells me but it isn't getting me anywhere.”

Leicester council said "As we have not been provided with Ruth’s full name, we are not able to confirm that she approached us, and have no available background to draw on. More generally, we can confirm that we offer a range of support for people who are faced with homelessness.

"We are constantly reviewing how best we are able to support residents in the private rented sector and we would encourage anyone in housing need to contact us so that we can help."

The rollout of Universal Credit has affected landlords’ confidence in taking on tenants on housing benefit. A study by the Residential Landlords Association found that more than half of private landlords who let to tenants on Universal Credit saw them fall into arrears.

A Bournemouth charity worker, who regularly sees people who are homeless struggling to rent, said: “There are only a handful of landlords round here willing to rent to people on housing benefits. With the university growing so much here that has driven the shared house and bedsit prices up, but I think it is less an affordability thing than discrimination.” The Bureau found just six affordable two-bed homes out of more than 600 in Bournemouth.

As well as working with the homeless, the charity worker is a private landlord himself. But a bad experience with a tenant on housing benefits has put him off letting to anyone else. “So I do understand why [landlords are reticent], but I appreciate that is tarring everyone with the same brush.”