Prime Minister Theresa May suffered her second defeat in a week over Brexit Tuesday when the House of Lords voted to give parliament the final say on how Britain leaves the European Union. Peers voted by 366 to 268 to amend the bill empowering May to trigger Article 50 of the EU's Lisbon Treaty, the formal notification of Brexit which she has promised to issue by the end of March.
She remains confident she will meet that deadline, but the defeat is a setback - as well as a taster of the trouble she could face from lawmakers as she embarks on complex EU negotiations.
The amendment would give parliament the power to reject the final Brexit deal agreed with the EU - a move critics said was akin to a "veto" which would damage the government's negotiating hand.
Ministers would still be constrained by the strict Article 50 timetable, however, which means that Britain will leave the EU after two years whether it has struck a withdrawal agreement or not.
The defeat comes after peers defied the prime minister for a first time on March 1, to include in the bill guarantees for more than three million European citizens living in Britain after Brexit.