Brexit is not the only constitutional issue of our time – the roles of attorney general and lord chancellor must be addressed.

I watched most of the Brexit cases on the Supreme Court’s video feed. I got a bit obsessed. This was partly because, in modern parlance, I had ‘skin in the game’. I am on the board of an organisation associated with one of the Northern Ireland cases. But this provided an excuse rather than a reason. My fixation was generated more by the constitutional importance and range of the issues manifest in the cases. These are massive, even if you ignore the subject matter of the litigation.

The cases were a triumph for the Supreme Court at every level. In 2001, I joined Justice. My very first event was the annual lecture given by Lord Bingham. He extolled the idea of a Supreme Court to replace the creaking House of Lords Judicial Committee. Someone remarked at the time that the lecture amounted to a job application. And so it proved.

The creation of the court changed nothing constitutionally: politically, these cases showed just how far we have come from an arcane addendum to the upper house. For a start, the court’s commitment to its public role paid off. The building looked great. The video worked. The world could see the justices doing their job – which has always been pretty impressive. No wigs, minimum formality, maximum concentration. Lord Bingham would be proud of what was, to a large degree, his creation.

The video disclosed one major discomfort. There must be few areas of public life where such a gender imbalance is manifest. The government’s whole legal team appeared to be white men. Only Lady Hale provided relief from the all-white male bench. And only one woman advocate was listed to address the court, Helen Mountfield QC (though I spotted Jessica Simor QC getting close to the lectern at one point). But most of the time the screen showed rows of men, some of whom were slightly younger than myself but no more diverse. That is not acceptable.

The government should ensure its legal teams display adequate diversity and it is past time for Lady Hale to be joined by female colleagues. Members of the court are statutorily required to be appointed ‘on merit’. Let us agree that merit not only means coming first but also meeting agreed criteria for appointment. That might open things up.

Two government ministers played a role in the case – one by his presence and the other by her absence. Attorney general Jeremy Wright QC opened the government’s argument. He wisely passed the baton to David Eadie QC just as soon as he decently could. The justices tactfully avoided questioning him, though Lord Neuberger pointedly confirmed that the government had objected to none of those sitting.

The lord chancellor got embroiled in a spat about the requirements of her oath of office, which includes a no-doubt tiresome requirement to ‘defend the independence of the judiciary’. This reflects the duty in section 3(1) of the Constitutional Reform Act 2005 that ‘the lord chancellor … must uphold the continued independence of the judiciary’. Liz Truss took the view that headlines in the Daily Mail along the lines of ‘Judges v The People’ did not require her to make a personal intervention.

There is a real problem here that goes beyond any allegation that these two individual politicians are lightweights. The role of attorney general is threatened by the professionalism of politics, which means that few MPs have the necessary legal experience. Wright does not impress. Dominic Grieve would be much better but he is far too much of a known Europhile and liberal. So Theresa May’s choice was narrow. Similarly constrained, Tony Blair parachuted Lord Goldsmith in from the Lords. That did not work out too well either.

It is time for the post of government legal adviser to be an independent statutory office to be consulted on a formal basis. It is hard to know what to do with the post of lord chancellor. Margaret Thatcher and John Major were blessed with probably the best incarnation of the office in its old form: Lord Mackay of Clashfern. But the office and its responsibilities are now a mess.

It would probably be better to disentangle justice from prisons, sending the latter back to the Home Office. That would leave a small but hopefully prestigious office whose role as the liaison between the executive and the judiciary might be better defined. The least that should be done is to delete experience as a member of either house of parliament as qualifying anyone for this office. Personally, I think that there should be a requirement for judicial experience. That would include advocates who had experience as a recorder or anyone who sat as a justice of the peace.

Once we get the judgments, debate will be all about their monumental consequences. But Brexit is not the only constitutional issue of our time. We need to address those above as well.  

Roger Smith is visiting professor at London South Bank University and former director of human rights group Justice