Remainer peers have again defeated the Government over Brexit after voting to scrap the time limit on Britain finally unshackling itself from the EU.
The House of Lords backed an amendment to the EU Withdrawal Bill to ensure March 29, 2019 is no longer fixed in law as the date the UK leaves the bloc.
Peers voted to remove the date from the bill by a majority of 78, with 311 backing the motion and 233 opposing it.
The vote is another blow for Prime Minister Theresa May who has already faced a number of Brexit challenges from the Lords.
Critics argue that unelected Remainer peers are trying to frustrate the will of British voters by slowing down the Government’s Brexit process.
But the Duke of Wellington, who led a cross-party move to delete the exit date, insisted he was trying to help the Government in its negotiations.
The Tory peer said: “We know beyond any doubt that for the purposes of this Bill, we leave the EU on March 29, 2019.
“But this date should not be defined and specified in case it becomes necessary and in the national interest to agree an extension as provided in Article 50.
“We should give ministers a bit more flexibility to secure and obtain ratification of the best possible deal, which will do the least damage to the economy and the national interest.”
Backing the amendment, Labour’s Baroness Hayter told peers removing the exit date would “make the task easier for negotiators”.
She said: “If this amendment is successful, it will remove the straitjacket that the Government are in, at the behest of certain ardent Brexiteers.
“Let’s get the straitjacket out, let’s make the task easier for negotiators.”
And Lord Newby, the Liberal Democrat leader in the Lords, said it had been a “very silly” move to include the date when flexibility made “eminent sense”.
But Brexit minister Lord Callanan told peers he saw “no reason” to amend the Bill in this way.
He said: “I would reiterate that exit day within the Bill does not effect our departure from the EU, which is a matter of international law under the Article 50 process.
“What it does effect, however, is whether we leave the EU in a smooth and orderly fashion.
“Crucially, the Bill left the Commons reflecting the reality of international law under the Treaty of the European Union and I see no reason therefore to change the Bill any further.”
Before the vote, Foreign Secretary Boris Johnson urged the upper house to respect the “clearly mandated” will of the people.
He said: “Both parties campaigned to come out of the single market and customs union. It is not just the referendum but in the general election too.
“There is a longstanding tradition in the UK that the House of Lords can under no circumstances frustrate what has been clearly mandated not just by a referendum but by the election as well.
“Indeed, they shouldn’t frustrate it under any circumstances because they do not represent they sovereign will of the British people.”