The home secretary is apologising to 18 members of the Windrush generation believed to have been wrongfully removed or detained.
A new Home Office review identified the group as having come to the UK from the Caribbean before 1973 and stayed permanently, but having not had documentation to prove their continued residence.
This led to them being removed or detained in an immigration removal or reporting centre.
Home Secretary Sajid Javid admitted these cases were where the Home Office was “most likely to have acted wrongfully” – the nearest ministers have come to confirming cases of wrongful removal or detention of legal UK citizens.
Of the 18, the review found 11 left the UK voluntarily with some having been served immigration papers telling them they had no right to be in the UK.
The government will help these 11 to return to the UK if they wish to do so, with one individual already having been supported.
The remaining seven were detained but subsequently released without being removed.
The Home Office has so far contacted 14 of the 18, with Mr Javid writing to them to offer a “full, formal apology” and making them aware of a government compensation scheme.
Mr Javid said: “The experiences faced by some members of the Windrush generation are completely unacceptable and I am committed to righting the wrongs of the past.
“I would like to personally apologise to those identified in our review and am committed to providing them with the support and compensation they deserve.
“We must do everything we can to ensure that nothing like this happens again – which is why I have asked an independent adviser to look at what lessons we can learn from Windrush.”
The figures were revealed in a letter from Mr Javid to Labour MP Yvette Cooper, chair of the House of Commons’ home affairs committee, in which he provided an update on the government’s response to the Windrush scandal.
Mr Javid had previously told the committee an initial Home Office examination of possible Windrush cases found 63 people had been removed or deported, of which 32 were deportations of foreign national offenders.
A new Home Office unit has since looked at a wider pool of 11,800 cases and found 164 possible examples of Windrush members being removed or detained.
That figure includes 74 people who appear to have left the UK for more than two years and therefore lost their entitlement to indefinite leave to remain and 72 who were briefly stopped at the border before being allowed to enter the country.
Officials aim to contact all 164 individuals.
In total, 6,507 people have now been referred to caseworkers on the government’s Windrush taskforce since it was established in April.
Some 2,272 have been issued with documentation to confirm their right to remain in the UK.
Earlier this year, Mr Javid’s predecessor Amber Rudd resigned as home secretary amid the scandal over the treatment of the Windrush generation; who are named after the cruise ship that brought one of the first large groups of West Indians to Britain after the Second World War in 1948.
Prior to quitting government, Ms Rudd had initially said she was not aware of any members of the Windrush generation who had been deported from the UK.
Anyone who entered the UK from Commonwealth countries before 1973 is legally entitled to live in the UK.
In his letter to Ms Cooper, Mr Javid said the Home Office analysis of Windrush cases “exposes problems which have happened over many years, under multiple governments”.
Labour’s shadow home secretary Diane Abbott branded Mr Javid’s apology as “overdue” and “nowhere near good enough”.
She said: “The government has still not got a final figure on how many of our fellow citizens were deported, forced into so-called ‘voluntary removals’ or detained as prisoners in their own country.
“It is an insult that the home secretary has still failed to confirm when the promised compensation scheme will be up and running, after so many of our fellow citizens have been left destitute, in debt and jobless by the government’s hostile environment.”