British Peers have inflicted a double defeat on their government over flagship Brexit legislation, amid claims they are attempting to prevent the UK leaving the EU.
Labour, the Liberal Democrats, Crossbenchers and backbench Tories formed an alliance over amendments to the European Union (Withdrawal) Bill, with one seeking to retain the option of a customs union with the EU and the other to protect people's rights post-Brexit.
When one of the customs union amendments was pushed to a vote, peers voted overwhelmingly in favour by 348 votes to 225 - majority 123 - with another, linked amendment approved unopposed.
The House of Lords Library reported the 573 peers involved in the vote was the seventh largest turnout ever in the chamber's history, and included a sizeable Tory rebellion.
A total of 24 of the party's peers supported the amendment, including former cabinet ministers Lord Heseltine, Lord Lansley and former minister Lord Willetts.
The House of Lords have given the Commons a great opportunity to have a proper and full debate on the impact of leaving the #CustomsUnion and to put a break on Theresa May’s plans for a hard and destructive #Brexit.https://t.co/7u1eA45FDY— Chuka Umunna (@ChukaUmunna) April 18, 2018
Meanwhile, former British prime minister David Cameron has said he does not regret holding the Brexit referendum, but believes Britain chose the wrong course.
He told CNN: "I don't regret holding a referendum. I think it was the right thing to do.
"I don't think you can belong to these organisations and see their powers grow, and treaty after treaty, and power after power going from Westminster to Brussels and never asking the people whether they are happy governed in that way.
"But, I haven't changed my mind about the result of the referendum. I wish the vote had gone another way.
"I think we have taken the wrong course."
Reacting to the Lords votes The Department for Exiting the European Union expressed its disappointment at the result.
Brexit minister Lord Callanan said the Government did not support the customs union measures as it would require it to report to Parliament on the steps taken towards delivering an objective it has "clearly ruled out".
He signalled the Government's intention to overturn the measures at a later stage, saying before the vote it had no intention to "reflect further" on the matter.
A later vote on amendment 11 - a cross-party move from peers to ensure that existing protections across a range of areas including employment, equality, health and safety and consumer standards cannot be changed except by primary legislation - was approved by 314 votes to 217, majority 97.
The division list showed there were 14 Tory rebels on this vote.
The Bill transfers EU law into UK law but concerns have been raised over the use of so-called Henry VIII powers, which would allow ministers to amend EU rules and regulations when they are transferred on to the UK statute book with little parliamentary scrutiny.
Lord Callanan argued that he believed the Government had already taken steps to address the concerns, "potentially in ways that are even stronger than (Labour peer Lady Hayter's) amendment".
The Lords have put their country first and rebel Conservative peers have been particularly brave. I know many Conservative MPs privately share their support for a customs union/arrangement. I hope they will not vote to remove this wholly sensible & responsible amendment.— Anna Soubry (@Anna_Soubry) April 18, 2018
Crossbench peer Lord Kerr of Kinlochard, an author of Article 50, opened the Bill's report stage by moving the cross-party customs union proposal and arguing there is a need to try to "limit the damage" of the UK leaving its largest market.
Lord Kerr said: "The country voted narrowly to leave the European Union, but no one can argue that it voted knowingly to leave the customs union with the European Union."
Tory former Cabinet minister and European commissioner Chris Patten also supported the proposal, noting there were times in a political career where party loyalty "comes way behind trying to stand up for the national interest".
But Conservative Viscount Ridley said of the amendment: "It's an attempt to wreck this Bill and to prevent Brexit."
Earlier he took aim at the Lib Dems, saying: "Ricardo, Cobden, Gladstone, those great Liberals would be spinning in their grave at the thought that their descendant party today is in favour of this form of trade discrimination."
Conservative former chancellor Lord Lawson of Blaby said Vote Leave made it "absolutely clear" leaving the EU meant leaving the customs union and single market.
He dismissed trade arguments in favour of a customs union with the EU, adding: "I urge the House to reject what is in essence a wrecking amendment."
Crossbench peer Lord Bilimoria, the founder of Cobra Beer, said the amendment was about "damage limitation" as he supported the UK remaining in the customs union.
Conservative former cabinet minister Lord Forsyth said the change being sought in relation to a customs union was "an attempt to create division and confusion" in the House of Commons in a bid to block Brexit.
He said it was seeking to make the UK's withdrawal form the bloc "subject to some conditions about a customs union".
He warned the amendments put forward in the unelected chamber were "putting the peers against the people".
Lord Forsyth said: "What is going on here is an exercise by Remainers in the House who refuse to accept the verdict of the British people and I believe they are playing with fire."
Labour's Baroness Hayter of Kentish Town said the amendment was "good for the governance of this country" and would save the economy £24 billion over the next 15 years.
In a statement, a Department for Exiting the European Union spokeswoman said: "We are disappointed that Parliament has voted for this amendment.
"The fundamental purpose of this Bill is to prepare our statute book for exit day, it is not about the terms of our exit.
"This amendment does not commit the UK to remaining in a customs union with the EU, it requires us to make a statement in Parliament explaining the steps we've taken.
"Our policy on this subject is very clear. We are leaving the customs union and will establish a new and ambitious customs arrangement with the EU while forging new trade relationships with our partners around the world."