Corbyn has the capability to shape the contours of Brexit, but he’s not using it

If he wishes to, with the parliamentary equivalent of an imperial thumbs down Mr Corbyn could cement the UK’s position in the EU customs union

The fact that the cabinet is as divided as the Labour Party is scant consolation to anyone (Getty)

Like a Roman emperor, Jeremy Corbyn has the power of life and death over the Conservative government. You would think it was a dream come true for him, the last step on his long march to power, but he seems curiously disinclined to make the most of the historic opportunity. That is bad for Britain and bad for the people which the Labour Party aspires to help.

If he wishes to, with the parliamentary equivalent of an imperial thumbs down, Mr Corbyn could cement the UK’s position in the EU customs union by backing the existing amendment to the Brexit bill to that effect. The amendment is one of 15 proposed by the House of Lords. If Mr Corbyn rallied his MPs to that cause, which is the nearest thing to Labour’s own formal (unworkable) policy of “a” customs union, it would cause a crisis in the Conservative Party.

The move would very likely end Theresa May’s unhappy premiership and trigger an election and another referendum on the EU question in the process. Much the same would happen if Mr Corbyn also followed the Lords’ advice and committed the UK to remaining in the EU single market, via the European Economic Area (EEA). Mr Corbyn could find himself in No 10 before even he thinks likely, there to fight for the causes he has so long devoted himself to. He would be in a position to negotiate reforms from within the EU. He would also, as a useful side effect, save the UK economy. It would not be a bad day’s work.

Instead, the Labour leader seems content to waver, his thumb resolutely wobbling over the prone body of the May government, which ought really to be out of its misery. Keir Starmer pleads that Labour is too divided to back EEA membership. This is only partly convincing. Labour doesn’t need to be completely united in the Commons to deal the government a fatal blow and Mr Corbyn has never shown much concern about party division when he wants to push something through.

Labour has now revealed its single market counterpart to the policy of forming “a” customs union with the EU. In essence it proposes that the UK should be allowed access to the single market, as now, but without the bits it finds irksome. It is, as Mr Corbyn’s critic Owen Smith points out, a prime example of “cakeism” – yet another attempt by the British to have their cake and eat it. For whatever reason – whether it may be politeness, diplomacy or tactical manoeuvring – the European Commission has chosen not to ridicule Labour’s ideas. Michel Barnier has not revealed how he would feel about having Barry Gardiner tagging along for the EU’s international trade negotiations, but it is easy to imagine his reaction. Politically, Labour’s policy lets Ms May off the hook and makes the party look silly.

The fact that the cabinet is as divided as Labour is scant consolation to anyone. Mr Corbyn is right to press the government to publish their promised “detailed, ambitious and precise” white paper on Brexit, but he would be a little more convincing if his own policies did not amount to much more than wishful thinking. As things stand, the British people are faced with a choice between two main parties, neither of which has a policy on Brexit that either commands support in their own ranks or which will be accepted as a basis for talks by Brussels. The Liberal Democrats, the SNP and other parties do have clarity and unity, but have little or no chance of forming a British government. This is almost as bad as things can be.

Only two encouraging developments have emerged recently. First, Ms May’s backstop position seems to no longer be that “no deal is better than a bad deal” and may resort to an indefinite membership of the customs union until such time as her favoured options of “maximum facilitation” or a streamlined, high-tech “customs arrangement” actually become workable. That could be a very long time indeed.

Second, Mr Corbyn has refused to rule out a so-called second referendum – in reality the first referendum where the British people will have a full picture of what the future may hold for them. It would also be a final referendum in the sense that this time around it would amount to a “fair fight”, with the likely package known, the benefits and costs of Brexit much more widely appreciated and rather more vigilance about spending and foreign interference.

The latest warning from the European Commission to EU firms about importing British componentry underlines the disaster waiting to overtake industries after Brexit. The Freight Transport Association say “not a single one” of their concerns have been dealt with and that Britain is “on the road to nowhere”. It bears repeating that any friction at the British border will damage the economy and jobs. Not to forget that the Good Friday Agreement and peace and prosperity in Ireland, all crucially depend on the UK remaining in the customs union and ideally, the single market. The hard, logical choices that crystallised immediately after the EU referendum remain unresolved.