In her concluding remarks at PMQs, Mrs Badenoch said: “The Prime Minister has consistently backed criminals over law-abiding British people.
“He defended terrorists, like Hizb ut-Tahrir in the European court. He argued all immigration law had a racist undercurrent. He voted against life sentences for people smugglers.
“He voted against more than 100 measures to control migration. He even said it was wrong when the Conservatives took away Shamima Begum’s citizenship.”
Ms Begum, who has been living in a Syrian refugee camp, was stripped of her citizenship after travelling to so-called Islamic State-controlled territory in the country as a 15-year-old in 2015.
Mrs Badenoch added: “Events in Syria mean we may see more small boat arrivals. For once will he take the side of the British people and strip citizenship from jihadi terrorists and supporters of Assad who want to come back and destroy this country?”
Sir Keir replied: “I was director of public prosecutions for five years. Unlike anyone on their benches, I was prosecuting for five years, hundreds of thousands of criminals, that includes huge terrorist gangs.
“I was working for three of those five years with the then-home secretary Theresa May, who commended the work that I did at the end of those five years. So for her to stand there and say, ‘I haven’t done anything in law enforcement’, I dedicated five years of my life to law enforcement, locking up criminals, which is more than she can say.”
Labour has previously said Sir Keir was asked to give advice to Hizb ut-Tahri in a legal dispute between the group and the German government, adding he did not formally represent them.