Jeremy Corbyn has suggested Boris Johnson could have been deported to the US because he "dabbled in class A drugs" and "conspired" to beat up a journalist when he was younger, as he questioned the government's decision to deport foreign criminals to Jamaica.
There was furious reaction from Tory benches when the Labour leader asked if there was "one rule for young black boys from the Caribbean and another for white boys from the United States".
Mr Corbyn, referring to a flight which took 17 convicted criminals to Jamaica on Tuesday, said the deportation showed the Government had learned "absolutely nothing from the Windrush Scandal".
Mr Johnson - who was born in New York - hit back, saying Mr Corbyn had conflated the Windrush generation with what he described as "foreign national offenders".
The Government says it is legally obliged to order the deportation of foreign criminals who had received sentences of 12 months or more in prison.
But campaigners say some of those due on the flight were sentenced for one-time drug offences when they were young and came to the UK when they were children.
Some 33 people due to be deported were spared after a last-minute legal battle between the Government and human rights campaigners.
On Tuesday, ministers including Home Secretary Priti Patel, defended the deportation saying those on the flight were foreign criminals who committed serious offences.
But campaigners, supported by more than 170 MPs, say many on the flight are "British in every meaningful way".
Speaking at Prime Minister's Questions, Mr Corbyn asked Mr Johnson if he thought a person who entered the UK aged five "and was the victim of county lines grooming and compelled to carry drugs, released five years ago and never re-offended, deserves to be deported?"
Mr Johnson replied: "I think the whole country would agree that, while I cannot comment on individual cases, it is entirely right that foreign national offenders should be deported from this country in accordance with the law."
Mr Corbyn said the Government was misleading the public by claiming all those on the flight were serious offenders.
To groans from the Tory benches, Mr Corbyn added: "If there was a case of a young white boy with blonde hair who later dabbled in class A drugs and conspired with a friend to beat up a journalist, would he deport that boy - or is it one rule for young black boys from the Caribbean and another for white boys from the United States?"
Mr Johnson fired back: "Mr Corbyn demeans himself and by the way besmirches the reputation of the Windrush Generation who came to this country to work in our public services, to teach our children in this country, to make lives better for people in this country.
"He has no right to conflate them with those foreign national offenders that we are deporting today."
Members of the Windrush Generation came to the UK from Caribbean countries - many on the boat HMS Empire Windrush - and were given a legal right to work in the UK following World War II.
The Windrush scandal relates to those who were wrongly detained, denied legal rights, threatened with deportation and wrongly deported from the UK by the Home Office.
Mr Corbyn's remark about a "young white boy with blonde hair who later dabbled in class A drugs" is reference to comments American-born Mr Johnson has made regarding cocaine.
When being interviewed by Janet Street-Porter for Marie Claire magazine, Mr Johnson confessed to taking drugs when he was a teenager.
When asked about taking cocaine, he replied: "Well, that was when I was 19. It all goes to show that sometimes it’s better not to say anything. I thoroughly disagree with drugs. I don’t want my kids having drugs.”
He was being asked about an appearance on panel show Have I Got News For You in 2005, in which he said: "I think I was once given cocaine, but I sneezed and so it did not go up my nose. In fact, I may have been doing icing sugar.”