She had previously insisted she was not aware of any Windrush citizen being wrongly deported.
Today, Home Secretary Sajid Javid has admitted that more than 60 people caught up in the Windrush scandal may have been wrongly deported, and there could be more.
Home Office officials have scoured through 8,000 records since 2002 and up to 63 people, aged over 45, could have been expelled from Britain, 32 of whom were labelled foreign national offenders, and 31 administrative removals.
Although Mr Javid stressed the figure was provisional, his admission gave an indication of the scale of the exercise facing the Home Office.
Sajid Javid, who took over as home secretary, or interior minister, on April 30 after Amber Rudd was forced to resign over her handling of the Windrush scandal, appeared on Tuesday in front of a committee of lawmakers investigating the scandal.
When he was appointed last month, Mr Javid said he would scrap the Home Office's so-called "hostile environment" policy which led to so many people who came from the Caribbean before 1973 to fall foul of the immigration authorities.
He said: "I've asked officials to be absolutely certain and thorough and check over every record and make sure".
According to a letter sent to MPs on the committee by Home Office permanent Secretary Sir Philip Rutnam, there have been 17 cases where deported Windrush immigrants have returned to the United Kingdom since 2015.
Almost 1,500 appointments had been booked, resulting in 526 people receiving documents which confirmed their right to live in Britain, he said.
However, he said he did not yet have data on how many Windrush immigrants had been detained.
The Labour MP David Lammy said: "This is the worst human rights and home affairs crisis in my time in politics".
Although fully entitled to live and work in the United Kingdom, an unknown number of Windrush descendants have been wrongly identified as illegal immigrants and denied basic rights such as healthcare.
Sadiq Khan responded to the news on Twitter.