I am an enemy of the people. Or so the Daily Mail would probably have you believe. For I am a peer and this week I will be voting against Theresa May’s hard Brexit in the hope of inflicting the government’s first Brexit defeat in parliament – and, far more importantly, voting for the right of EU nationals to remain in the UK.

The greatest charge usually levelled against peers is an alleged tendency to look a little somnolent on the red benches. But tomorrow, what goes on in the House of Lords matters more than any day I can remember. We have a huge opportunity to save countless families from being ripped apart, by forcing the Government to do the decent thing and guarantee the right of all EU citizens to remain in the country where they have built their lives, and in the process built up the UK economy.

It’s easy to rubbish the Lords whenever the Government wants to roll over us. But we’re an essential element in our parliamentary democracy. The Lords is a revising chamber. We do not block government legislation, but we can ask them to justify proposals that ministers put forward – and frequently do.

The Commons is far more partisan, dominated by the clash between government ministers and their opposition shadows. Proposals get through there on ambition, loyalty and whipping.

The Lords focuses more deliberately on whether proposals make sense, on the evidence behind them and the details on how they might work. Bills are much more often amended in the Lords than in the Commons, as ministers yield to careful arguments that make them adjust their plans.

What experts have said about Brexit Show all 11 1 /11 What experts have said about Brexit What experts have said about Brexit Chancellor of the Exchequer Philip Hammond The Chancellor claims London can still be a world financial hub despite Brexit “One of Britain’s great strengths is the ability to offer and aggregate all of the services the global financial services industry needs” “This has not changed as a result of the EU referendum and I will do everything I can to ensure the City of London retains its position as the world’s leading international financial centre.” Reuters What experts have said about Brexit Yanis Varoufakis Greece's former finance minister compared the UK relations with the EU bloc with a well-known song by the Eagles: “You can check out any time you like, as the Hotel California song says, but you can't really leave. The proof is Theresa May has not even dared to trigger Article 50. It's like Harrison Ford going into Indiana Jones' castle and the path behind him fragmenting. You can get in, but getting out is not at all clear” Getty Images What experts have said about Brexit Michael O’Leary Ryanair boss says UK will be ‘screwed’ by EU in Brexit trade deals: “I have no faith in the politicians in London going on about how ‘the world will want to trade with us’. The world will want to screw you – that's what happens in trade talks,” he said. “They have no interest in giving the UK a deal on trade” Getty What experts have said about Brexit Tim Martin JD Wetherspoon's chairman has said claims that the UK would see serious economic consequences from a Brexit vote were "lurid" and wrong: “We were told it would be Armageddon from the OECD, from the IMF, David Cameron, the chancellor and President Obama who were predicting locusts in the fields and tidal waves in the North Sea" PA What experts have said about Brexit Mark Carney Governor of Bank of England is 'serene' about Bank of England's Brexit stance: “I am absolutely serene about the … judgments made both by the MPC and the FPC” Reuters What experts have said about Brexit Christine Lagarde IMF chief urges quick Brexit to reduce economic uncertainty: “We want to see clarity sooner rather than later because we think that a lack of clarity feeds uncertainty, which itself undermines investment appetites and decision making” Getty Images What experts have said about Brexit Inga Beale Lloyd’s chief executive says Brexit is a major issue: "Clearly the UK's referendum on its EU membership is a major issue for us to deal with and we are now focusing our attention on having in place the plans that will ensure Lloyd's continues trading across Europe” EPA What experts have said about Brexit Colm Kelleher President of US bank Morgan Stanley says City of London ‘will suffer’ as result of the EU referendum: “I do believe, and I said prior to the referendum, that the City of London will suffer as result of Brexit. The issue is how much” What experts have said about Brexit Richard Branson Virgin founder believes we've lost a THIRD of our value because of Brexit and cancelled a deal worth 3,000 jobs: We're not any worse than anybody else, but I suspect we've lost a third of our value which is dreadful for people in the workplace.' He continued: "We were about to do a very big deal, we cancelled that deal, that would have involved 3,000 jobs, and that’s happening all over the country" Getty Images What experts have said about Brexit Barack Obama US President believes Britain was wrong to vote to leave the EU: "It is absolutely true that I believed pre-Brexit vote and continue to believe post-Brexit vote that the world benefited enormously from the United Kingdom's participation in the EU. We are fully supportive of a process that is as little disruptive as possible so that people around the world can continue to benefit from economic growth" Getty Images What experts have said about Brexit Kristin Forbes American economist and an external member of the Monetary Policy Committee of the Bank of England argues that the economy had been “less stormy than many expected” following the shock referendum result: “For now…the economy is experiencing some chop, but no tsunami. The adverse winds could quickly pick up – and merit a stronger policy response. But recently they have shifted to a more favourable direction” Getty

So far, the Government’s plans on how to leave the EU are horribly unclear. The White Paper the Prime Minister reluctantly published ducks many of the difficult questions. Special arrangements for specific industries will be fiendishly difficult to negotiate or administer. Open borders for trade are incompatible with leaving the customs union and the European regulatory framework. Insistence on complete sovereignty from rulings of the European Court of Justice will block continued participation in the extensive network of police cooperation, data sharing and intelligence that has grown up since the end of the Cold War, which relies upon agreed checks on misuse of authority to retain mutual confidence.

Brexiteers insist that the people made their decision on June 23rd, and that Parliament has only a minor role to play on how the government interprets that decision. But the devil is always in the detail, and the referendum campaign left the details of leaving the EU undefined.

The whole idea of parliamentary democracy is that the government is held to account day by day and week by week, not just by occasional referendums. Whether to stay within the single market, how to maintain security cooperation with our neighbours, how to prevent long queues of people and goods at Britain’s frontiers once we leave the EU, are all vital issues from Britain’s future on which Theresa May and her Government have so far provided incoherent answers.

Labour’s abdication of responsible opposition in the Commons makes the role of the Lords even more important. Of course it’s difficult to defend this unelected Chamber – and it suits an embattled government to threaten abolition whenever it is in a corner.

But the advantage of the Lords, even in its current unsatisfactory state, is that its appointed members understand their role as limited but legitimate: to challenge the government when the Commons fails to do its job, to ask awkward questions and to demand reasoned answers.

Sir John Major criticises Theresa May's Brexit strategy

How the UK leaves the EU is the most important political issue facing the UK. Get it wrong, and the country will be poorer and less secure. In the eight months since the referendum, Brexiteers have repeatedly attacked their critics for their doubts without explaining what future relationship with the countries across the English Channel they want to negotiate.

Of the key ministers, only David Davis seems to have grasped the complexities of Brexit. Liam Fox has travelled to distant lands without making much impact, while Boris Johnson has puzzled and irritated his opposite numbers by the obscurity of his language.

So the Lords, on behalf of the people, the national interest, British industry and British consumers, have the right to ask the Government to think again. My colleagues and I will be voting, this Wednesday, to demand clearer answers – and we will continue to ask for answers as the process of negotiating exit edges uncertainly forward.