THERESA May laid the blame for the Windrush scandal at Labour's feet as Jeremy Corbyn accused her of making the Home Office "heartless".
The Prime Minister denied she was responsible for the immigration row which has seen some older Britons denied NHS, cost others their jobs and landed more in detention centres.
Yesterday it emerged that the landing cards of Windrush arrivals had been destroyed by the Home Office in 2010 – while May was Home Secretary.
But in the House of Commons, May said the decision to trash the documents – which would have provided some evidence for people ordered to prove their right to live in the UK – had been taken under the last Labour government in 2009.
In a heated exchange, Corbyn insisted May, who led the Home Office until 2016, should take responsibility for shredding the slips creating a "hostile environment" for migrants in pursuit of lower immigration targets.
He said: "It led to British citizens being denied NHS treatment, losing their jobs, homes and pensions, thrown into detention centres like criminals and even deported.
"Isn't it the truth, Mr Speaker, that under her the Home Office became heartless and hopeless and does she not now run a government that is both callous and incompetent?"
Hitting back, May said: "I will not take an accusation of 'callous' from a man who allows anti-Semitism to run rife in his party."
Beginning Prime Minister's Questions, May offered a fresh apology to those caught up in the scandal, which has affected the children of Commonwealth citizens who came to the UK in the post-war reconstruction period.
She said: "These people are British, they are part of us. I want to be absolutely clear that we have no intention of asking anyone to leave who has a right to remain here.
"For those who have mistakenly received letters challenging them, I want to apologise to them."
On the landing cards, former Labour Home Secretary Jacqui Smith said destroying the landing cards was "not a policy decision" she had made. Her successor Johnson, who took the role in June 2009, also said he had "absolutely no recollection at all" of involvement in that decision.
A Downing Street spokesperson said it was carried out as part of an "operation decision" made by UK Border Force in order to comply with data protection rules.
And the Home Office said the cards did not provide proof of continuous residence in the UK, claiming education and employment records are better alternatives.
Earlier in the day, Labour's Diane Abbot had called on current Home Secretary Amber Rudd to reconsider her position.
However, May said the cabinet minister had acted "swiftly".
The row has played out as leaders from 52 Commonwealth countries attended talks in London.
Despite the admission by Immigration Minister Caroline Nokes on Monday that some people may have been deported "in error", May today insisted there was no evidence of any specific cases.
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