Sir Keir warned that laws must be “applied in the circumstances as they are now” before adding that countries were experiencing “mass migration in a way that we have not seen in previous years”.
To meet this new challenge “we need to look at again at the interpretation of some of these provisions, not tear them down”, he said.
On the issue of deportation, he was asked about the example of a Brazilian paedophile who successfully claimed he would be treated worse in a Brazilian prison than he would in a British prison.
The prime minister drew a line between deporting someone to “summary execution” and claims based on worse healthcare or prison conditions abroad.
“I believe that those genuinely fleeing persecution should be afforded asylum and that is a compassionate act,” he added.
Pressed for details about what was blocking deportations of foreign criminals, Sir Keir cited Articles 3 and 8 of the ECHR – which ban torture and protect the right to private and family life respectively.
“But it’s more than that,” he said, pointing to the UN’s Refugee Convention, Torture Convention and Convention on the Rights of the Child as potential barriers.