The government has been defeated after the House of Lords said ministers should guarantee EU nationals’ right to stay in the UK after Brexit.
The vote, by 358 to 256, is the first Parliamentary defeat for the government’s Brexit bill.
However, MPs will be able to remove their changes when the bill returns to the House of Commons.
Ministers say the issue is a priority but must be part of a deal protecting UK expats overseas.
It remains to be seen whether or not it will delay the triggering of Article 50, or even if it will push it back beyond the original deadline at the end of March.