Thousands of landing cards – recording dates of arrival in the UK – were thrown away, despite staff warnings that it would be harder for Caribbean-born residents to establish their right to be in the UK.
The files were discarded in October that year, when the current prime minister was home secretary, a former Home Office employee revealed.
“This revelation from a whistleblower reveals that the problems being faced by the Windrush generation are not down to one-off bureaucratic errors, but as a direct result of systemic incompetence, callousness and cruelty within our immigration system,” he said.
“It is an absolute disgrace that the Home Office has destroyed these documents and then forced Windrush-generation migrants to try and prove their status, threatening them with deportation and stripping them of their rights.
“This was no accident and the orders to destroys records must have come from somebody at the top of the department.”
On Monday, the home secretary Amber Rudd admitted to “appalling” cases of people denied health treatment, stripped of their jobs and faced with deportation to countries they left as children decades ago, and have never returned to.
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Those affected lacked documents to prove to the Home Office – under tough new rules, introduced by Ms May – that they had the right to be in the UK.
But the former employee, speaking to The Guardian, said the landing card records, dating back to the 1950s, had been stored in the basement of a government tower block.
In October 2010, the Home Office decided to destroy the cards, when its base in Croydon was closed and the staff were moved to another, smaller site, he said.
Yet, a person’s arrival date was potentially crucial proof because the 1971 Immigration Act gave people who had already moved to Britain indefinite leave to remain.
From around 2013 onwards, after Ms May’s “hostile environment” crackdown, the number of requests from people wanting to know their arrival date from the Caribbean began to increase, the ex-staff member said.
“Every week or two, someone would say: ‘I’ve got another one here,’” he said.
“People were writing to say: ‘I’ve been here 45 years, I’ve never had a passport, I’ve never needed a passport. Now I’m being told I’m not British, because there is no record of me’.
“Because it was no longer possible to search in the archive of landing cards, people would be sent a standard letter that would state: ‘We have searched our records, we can find no trace of you in our files.’”
The decision was not taken on data protection grounds, but because of a lack of storage space in the new building, he added.
The Home Office, which has acknowledged that cards were discarded, has been asked to comment on the revelation.