Home Office mistreatment of immigrants goes far beyond the Windrush generation and affects thousands of refugees and asylum seekers, according to new research which concludes that the “dehumanising” approach is systemic.

The report, published by Refugee Action, highlights the issues that occur at multiple points in the asylum process and alleges that “systemic failures” in the Home Office’s approach to asylum claims “dehumanises, disempowers and damages” those who have come to the UK fleeing persecution or war.

Stephen Hale, chief executive of Refugee Action, said the detention, destitution, homelessness, and limbo faced by Windrush children were just the tip of the iceberg, and were widely familiar to asylum seekers. “All of the things those people have been through are also experiences that people are going through as result of asylum system,” he said.

The report highlights several “pressure points” in the asylum process that tend to cause problems for asylum seekers or refugees.

These include long waiting times that asylum seekers face for their claims to be decided by the Home Office. By the end of 2017, 14,306 people had been waiting for a decision on their asylum claim for more than six months, which is the current “service standard” for asylum claims. This is a 25% increase from 2016, despite the number of applications for asylum falling in 2017.

The report also details the number of incorrect decisions on asylum claims made by the Home Office. In 2017, 35% of asylum appeals resulted in Home Office refusals being overturned. For certain nationalities more than half of all appeals were upheld, including cases of people from Yemen (70%), Libya (61%), Somalia (54%) and Afghanistan (52%).

Some refugees told the researchers about how the interpreter provided for their Home Office interview – their key opportunity to explain their reasons for seeking refuge in the UK – did not correctly interpret what they said. Some also said they had not been able to access legal advice before the interview and had no clear point of contact to ask about their case.

“The human issues here are the length of time to take decisions, and the absolute lack of clarity on how long those decisions might take,” said Hale. “So people who are waiting two, three, four years, but without knowing if indeed it might be 15 years. People have been left in limbo – a time in which they have got incredibly low levels of income, no right to work, no place they can make their own in terms of housing. They really are abandoned.”

The report calls for people to be allowed to work and study while they wait for their asylum claim to be decided and describes the allowance given to asylum seekers of £37.75 per week as “problematic”.

Hale said the Home Office often dealt with problems in a piecemeal way and called for a “fundamental reset” of the system.

“The reality is that in making one issue better they will often make another issue worse and that’s why we think it’s important to take a systemic approach,” he said.

“The vast majority of the British people, I’m absolutely certain, would recognise we’ve got to find better ways to do this, that we can be a country that is compassionate, that is supportive of people who have had to flee the conflicts that are reported on our TV screens.”

A Home Office spokesperson said: “The UK has a proud history of granting asylum to those who need our protection. In 2017 there were just under 15,000 grants of asylum, alternative protection or resettlement, of whom almost 6,000 were children.

“We are committed to transforming the asylum system. We are modernising our processes and have established a new team to focus on more complex cases to make sure that they are decided faster.”

Mohmand’s case

Mohmand left Afghanistan in April 2013 after more than a decade of threats, abuse, and kidnapping attempts for his work exposing human rights abuses.

It took the Home Office three years and 11 months to give him refugee status and his case was marked by a litany of Home Office mistakes, including them losing his documents, repeatedly postponing his interview and wrongly refusing his claim.

“I felt it was not handled in care,” he says of his case.

Mohmand waited four years for the Home Office to grant him refugee status Photograph: Christopher Thomond/The Guardian

Mohmand was able to bring most of his family to the UK last December under family reunion provisions, which allow refugees to reunite with their spouse and dependent children under the age of 18.

However, as a result of the Home Office’s delays to his case, Mohmand’s two oldest children, who were 15 and 17 when he left Afghanistan, were 19 and 21 by the time he got refugee status, and had their applications to accompany the rest of their family refused.

Mohmand is particularly worried about his daughter Shireen, who lives virtually under house arrest in Kabul, because it is not safe for her to leave the house without the protection of her father or another older male relative.

“It is very much like a broken family,” he says. “You cannot concentrate on work, on children’s education, other future, you are always thinking of how you can bring together a broken family.”

Leila’s case

Leila, 23, arrived in the UK in 2010 when she was 15, fleeing Pakistan with her mother and father after the Taliban made threats against them because one of Leila’s brothers worked for the British army.

Their case, subsequent appeals and fresh claims were all refused, even after her other brother and sister back in Pakistan were shot and killed by the Taliban in 2014. A judge finally granted Leila and her parents asylum last year, almost seven years after they arrived in the UK. Leila had been able to attend school, but once she graduated she was not allowed to work or study and spent four years feeling like she was living in “a cage”.

“They just kill you by not letting you do anything,” she said. The impact was particularly profound on her father, 61, whom she said was “perfectly fit” when he arrived in the UK, but had had four heart attacks and a minor stroke since being in the country, which she put down to the stress and uncertainty of their situation. These incidents left him partially blind and unable to walk long distances.