An investigation into the extent of institutional racism within the Home Office must be launched in response to a damning report on the Windrush scandal, an alliance of anti-racism groups has urged.

The call came after the long-awaited publication of the independent inquiry into the government’s handling of the scandal, which saw British citizens wrongly deported, dismissed from their jobs and deprived of services such as NHS care.

The inquiry – which prompted an official apology from the home secretary, Priti Patel – concluded that the Home Office demonstrated “institutional ignorance and thoughtlessness towards the issue of race”. It was commissioned after the Guardian’s reporting on the government’s “hostile environment” immigration policy led to the exposure of the scandal and eventually the resignation of the then home secretary, Amber Rudd.

In response to the findings, a consortium of 16 pressure groups called on Thursday for the Home Office’s immigration policies to be scrutinised to assess whether they are discriminatory.

While the report stopped short of describing the Home Office as institutionally racist, the government now needed to analyse why “Home Office culture, attitudes, immigrations and citizenship policies have repeatedly discriminated against black and ethnic minority British citizens,” deputy director of the race equality thinktank the Runnymede Trust, Zubaida Haque, said.

She added that the report made it “very clear that the injustice was not an accident, but a result of institutional failures to understand race and racism”.

In the report, the Home Office is blamed for operating a “culture of disbelief and carelessness”. It concludes that the failings are “consistent with some elements of the definition of institutional racism”.

Patel gave an official apology in the House of Commons on Thursday, saying: “There is nothing I can say today that will undo the suffering … On behalf of this and successive governments I am truly sorry.”

But Michael Braithwaite, 68, who was sacked in 2017 from his job as a special-needs teaching assistant at the London primary school where he had worked for more than 15 years (despite the fact that he had lived in the country for half a century) said he was frustrated to hear Patel make a new apology almost two years after the government first did so.

“It’s the same expression of empathy, and more promises like last time. It’s there to make us feel better, but things haven’t changed,” he said, adding that he wanted the government to dismantle its hostile environment policies.

His remarks were echoed by Elwaldo Romeo, 65, who was sent a letter by the Home Office in 2018 telling him that he was liable to be detained, and offering him “support on returning home” (despite the fact he had moved to the UK from Antigua 59 years earlier, aged four). “Two years on, why have we still got Windrush people living in dustbins and airports?”

Responding on behalf of Labour, the shadow home secretary, Diane Abbott, said: “The verdict that there are elements of institutional racism at the Home Office is damning, and means there must be a root-and-branch overhaul and change of culture.”

'Lambs to the slaughter': 50 lives ruined by the Windrush scandal Read more

The review, prompted by months of Guardian reporting on the consequences of the Home Office’s “hostile environment” policy, says the scandal was “foreseeable and avoidable”. It says warning signs of problems caused by the immigration policy – such as “racially insensitive” billboards telling people to “go home or face arrest” – were ignored.

There was a tendency to blame individuals caught up in the immigration regulations, the report says. They found themselves criticised for failing to obtain evidence of their status, even though when they tried to do so they were not provided with the right documentation.

The report’s author, Wendy Williams, an inspector of constabulary, said at its launch: “The Windrush generation has been poorly served by this country, a country to which they contributed so much and in which they had every right to make their lives. The many stories of injustice and hardships are heartbreaking, with jobs lost, lives uprooted and untold damage done to so many individuals and families.”

Williams said she met about 800 people, and many of the interviews had been extremely upsetting. She said one man had been in tears when he told her how he had lost his job and his home “in tragic circumstances”. He told her: “I can’t believe I have been treated like this by my beloved England.”

Williams said: “There were a number of examples that were equally as upsetting. There was an overwhelming sense of bewilderment. They couldn’t understand how this had been allowed to happen.”

The 275-page report said the roots of the problem could be traced back to racially motivated legislation during the 1960s, 70s and 80s.

Williams wrote: “While I am unable to make a definitive finding of institutional racism with the department, I have serious concerns that these failings demonstrate an institutional ignorance and thoughtlessness towards the issue of race and the history of the Windrush generation within the department, which are consistent with some elements of the definition of institutional racism.”

She said many people “felt a strong sense of Britishness and had no reason to doubt their status or that they belonged in the UK. They could not have been expected to know the complexity of the law as it changed around them.”

Q&A What is the Windrush deportation crisis? Show Hide Who are the Windrush generation? They are people who arrived in the UK after the second world war from Caribbean countries at the invitation of the British government. The first group arrived on the ship MV Empire Windrush in June 1948. What happened to them? An estimated 50,000 people faced the risk of deportation if they had never formalised their residency status and did not have the required documentation to prove it. Why now? It stems from a policy, set out by Theresa May when she was home secretary, to make the UK 'a really hostile environment for illegal immigrants'. It requires employers, NHS staff, private landlords and other bodies to demand evidence of people’s citizenship or immigration status. Why do they not have the correct paperwork and status? Some children, often travelling on their parents’ passports, were never formally naturalised and many moved to the UK before the countries in which they were born became independent, so they assumed they were British. In some cases, they did not apply for passports. The Home Office did not keep a record of people entering the country and granted leave to remain, which was conferred on anyone living continuously in the country since before 1 January 1973. What did the government try and do to resolve the problem? A Home Office team was set up to ensure Commonwealth-born long-term UK residents would no longer find themselves classified as being in the UK illegally. But a month after one minister promised the cases would be resolved within two weeks, many remained destitute. In November 2018 home secretary Sajid Javid revealed that at least 11 Britons who had been wrongly deported had died. In April 2019 the government agreed to pay up to £200m in compensation. Photograph: Douglas Miller/Hulton Archive

The report, which examined 69,000 official documents, noted that the Home Office does not have a large black and minority-ethnic workforce at senior level. “I think it is unfortunate that most of the policymakers were white and most of the people involved were black,” a senior official is quoted as saying in the report.

'Lambs to the slaughter': 50 lives ruined by the Windrush scandal Read more

The Windrush scandal unfolded after it became clear that the Home Office had wrongly designated thousands of legal UK residents as being in the country illegally.

Some were wrongly deported to countries they had left as children half a century earlier, and others were mistakenly detained in immigration detention centres.

The scandal led to the resignation in April 2018 of the then home secretary Amber Rudd and put Theresa May’s drive to create a “really hostile environment for illegal migration” under the spotlight.

In the past two years the government’s Windrush taskforce, set up to assist those affected, has given documentation to more than 8,000 people confirming that they have the right to remain in the UK.