The Supreme Court will on Monday begin hearing the most important constitutional case in the UK for many years. It will decide whether the Government needs the approval of Parliament to invoke Article 50 of the Lisbon Treaty and start two years of exit negotiations with the EU.

It is ironic that Brexiteers who fought the June referendum partly on handing back “control” to the UK Parliament seem remarkably reluctant to allow MPs and peers any influence over Brexit. It would have been much better if the Government had accepted the High Court’s ruling that Parliament must approve Article 50 than appealed – especially as only about 80 out of 650 MPs are likely to vote against the short bill needed to trigger negotiations.

Theresa May seems wary of any scrutiny of her Brexit strategy. Hiding behind her “no running commentary” mantra becomes more of a Whitehall farce by the day: now, even a letter from the Cabinet Secretary saying the Prime Minister has ordered a clampdown on leaks has been leaked. Ministerial discussions on such an important issue as Brexit were never going remain private. It would be much better for Ms May to go on the offensive and explain to a waiting nation what Brexit really means.

At least the latest smoke signals are more encouraging. It seems that May has realised that implementing the hard Brexit to which her rhetoric pointed would inflict serious damage to the economy. David Davis, the Brexit Secretary and a strong supporter of Leave, is showing welcome signs of pragmatism and flexibility. He is speaking about paying money to the EU for access to its markets and suggesting that some EU migration might continue in sectors where the economy needs it. This might not be a soft Brexit, but it would be softer and better than the leap into the dark of a hard Brexit with tariffs and possible trade deals with non-EU countries that might never materialise.

Of course, Brexiteers claim that anything other than a clean break with the EU would be to deny “the will of the people”. They point to statements in media interviews by some Leave campaigners during the referendum that Brexit would mean leaving the single market. Yet that was never spelled out clearly to voters, many of whom were swayed by promises about controlling immigration and getting “our money” back from Brussels.

In the Supreme Court, the Government will argue that the High Court relegated the June referendum to “almost a footnote”. No doubt Brexiteers will accuse the Supreme Court of frustrating “the will of the people” if it rules that Parliament must approve Article 50.