The Supreme Court’s welcome verdict sends the Brexit process back to where it should have been all along – Parliament. Theresa May created unnecessary uncertainty by appealing against the High Court's ruling. If she had accepted it, she would have won Parliament’s backing for legislation on Article 50 and would now be well on course to start exit negotiations with the EU by her 31 March deadline.

But will Parliament now step up to the plate? It’s far from certain and the omens are not good. There is probably a majority in the Commons and Lords to stay in the single European market, but that is unlikely to translate into a formal vote. The reaction of pro-European Conservatives to May’s announcement last week that the UK would leave the single market was instructive and they rolled over immediately.

Similarly, there is no majority in Parliament for the hard Brexit that May’s strategy could be taking us towards. A majority of MPs and peers probably regard that as an act of economic self-harm. But there is no guarantee that they will muster the votes to prevent it.

Too many MPs are frightened of their own shadows, and of being accused of trying to overturn last year’s referendum. Yet they know in their heart of hearts that even if a majority of their constituents voted Leave, they did not vote for a hard Brexit. So they would be entirely within their rights to exercise their judgement and soften the hard edges of Brexit, which is not the same as “thwarting the will of the people” or dictating the Government's stance in the tricky negotiations, as ministers claim.

Brexit round-up: Supreme Court rules against Government

A flurry of amendments to the Article 50 legislation have already been promised. But some – such as Labour’s attempt to safeguard workers’, social and environmental rights – may be ruled out of order because the Bill will be very tightly drawn. Demands for tariff-free access to the single market could be accepted by ministers at this stage, even though we don’t know whether the EU will agree to them in the talks.

The significant battles during the rushed passage of the Article 50 Bill will be over Parliament’s role during the negotiations. There will rightly be cross-party demands for MPs to have a real influence over the final deal, and the right to send May back to the EU table to get a better one. Her strategy is clear: to offer Parliament a last-minute choice between her deal and the “no deal” of World Trade Organisation tariffs, in the hope that Tory MPs vote through her agreement.

Labour is demanding a “meaningful” Commons vote on the deal. It is on the right track but its vagueness is typical of the timid response to Brexit by the official Opposition which has allowed May a much smoother ride than she has deserved. Only the Liberal Democrats, SNP and the Greens have spoken up for the 48 per cent so far.

Granted, Labour is being pulled in two different directions and Brexit would be a headache for any leader of the party. Two out of three Labour MPs represent seats that voted Leave but the overwhelming majority of the MPs backed Remain.

Brexit is the new dividing line in politics, exacerbating Labour's loss of support in the opinion polls under Jeremy Corbyn. The divide harms Labour most. The party holds 46 of the strongest pro-Leave seats – many in the North where Ukip is breathing down its neck – and it also represents 41 of the 100 most pro-Remain constituencies, including Corbyn’s and several of his shadow cabinet.

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

Two tricky by-elections next month in Copeland and Stoke-on-Trent Central have added another pressure.

Labour does not want to be accused of blocking Brexit but Corbyn has been unable to deliver the stronger line on immigration demanded by many Leave voters in the party’s heartlands. Under conflicting pressures from his Shadow Cabinet, he has flip-flopped, saying he is “not wedded” to EU free movement, but does not rule it out.

No wonder voters are confused about what Labour stands for. Brexit has added to Labour’s identity crisis and could make it an existential one.

At least we know where the Conservatives, Lib Dems and Ukip stand. However difficult the terrain, a leader has a duty to lead. Corbyn is not yet doing that on the issue of the day, the biggest challenge to the country since the Second World War.