The government has suffered a second Brexit defeat in the House of Lords as peers backed, by 366 votes to 268, calls for a “meaningful” parliamentary vote on the final terms of withdrawal.
Backing the move, former deputy PM Lord Heseltine said Parliament must be the “custodian of national sovereignty”.
Ministers said it was “disappointing” and would seek to overturn the move when the bill returned to the Commons.
The previous defeat was on the issue of guaranteeing the rights of EU citizens.
After a three-hour debate, peers amended legislation which will trigger official Brexit talks to require the final terms of the UK’s departure from the EU to be put to separate votes in the Commons and the Lords.