Judging by the look of its website on Tuesday morning, the Ministry of Justice still seems to be reeling a week after the replacement of almost all its ministers. There was little more on its main news page than a staged photograph of Chris Grayling, the new justice secretary and lord chancellor, being welcomed last Tuesday by his permanent secretary Ursula Brennan, herself only two months into the job.

From tweets reproduced on the same page one could discern the names of two of his junior ministers – Jeremy Wright and Helen Grant – but not the areas of work for which they will be responsible. Damian Green, the new minister of state who will be shared with the home office, was not mentioned. There was a brief comment attributed to Lord McNally, the only minister to keep his job, but clicking on the link took you to a speech by Crispin Blunt, who had lost his.

On policies, we were left almost totally in the dark. Brennan appeared to want her new justice secretary to tell her about his ‘vision for the justice system’. From Grayling’s own website, we learned that his ‘main focus’ will be ‘establishing a rehabilitation revolution’ – which I suppose means sending fewer criminals to prison. A lot has been written about the fact that Grayling is the first lord chancellor in modern times never to have qualified as a lawyer. After university, he joined the BBC’s news training scheme instead. I should add that I myself joined that scheme 10 years earlier, but I don’t believe we ever met. Grayling, now 50, also worked in media production and PR before his election to parliament in 2001.

As I argued in another column last week, we should attach rather more importance to the fact that, unlike his predecessors, Grayling must see his political career as in the ascendant. This matters because we can expect him to have an eye on how his policy decisions will be seen by senior colleagues and voters. There may be a place for populism in politics, but not when ministers are dealing with justice.

The appointment of a non-lawyer as lord chancellor has been inevitable for at least 25 years. Younger readers may not remember that legal aid was administered by the Law Society until 1989, when the government-run Legal Aid Board took over. Once the lord chancellor became responsible for the board’s resources – legal aid was then costing nearly £1bn a year – critics argued that he should become accountable to the elected house. And once he was in the Commons, the government could no longer be sure of finding a distinguished lawyer to take on the post. It followed that the lord chancellor could no longer choose the judges, sit as a judge himself or preside over the House of Lords.

That all fitted in with – and perhaps provided an excuse for – Tony Blair’s decision to sack Lord Irvine in 2003. Blair’s idea was to replace the lord chancellor with a secretary of state, presiding over a department of constitutional affairs. But abolishing the lord chancellor was far more difficult than Blair had imagined. Irvine’s successor, Lord Falconer, came to appreciate the strengths of 1,400-year-old post. So the Constitutional Reform Act 2005 preserves it, adding that appointees must appear to the prime minister to be ‘qualified by experience’.

Since that experience may include membership of parliament or ‘other experience that the prime minister considers relevant’, I cannot agree with Francis Bennion, the 89-year-old former parliamentary counsel, that Grayling’s legal inexperience renders his appointment void.

If things had remained where they were in 2005, Grayling would now be embarking on a role that was challenging but manageable. But in 2007, a few months before handing over to Gordon Brown, Blair decided that the lord chancellor should also take on the Home Office’s responsibilities for prisons, probation and the prevention of reoffending. The enlarged department became the MoJ.

If you are trying to keep the prison population within manageable bounds, it must be useful to have ministerial oversight of the judges who send offenders to prison. But only someone with a well-developed understanding of the rule of law will know how far he can go without trespassing on judicial independence, which the lord chancellor is required by the 2005 act to uphold. It is a tall order to expect this of a justice secretary who has never served in cabinet, supported by two junior ministers who have never held departmental office (one of them shared with another department) alongside a middle-ranking minster who is also shared and a minister in the Lords from another party.

So perhaps we should not be surprised that Grayling has not been burdened with the Justice and Security bill, introduced at the request of the security and intelligence services to permit courts to sit in secret. Getting that contentious bill through parliament remains the responsibility of Ken Clarke, whose membership of the National Security Council now makes him something of a minister for spooks.

Before 2003, it was becoming increasingly difficult for the lord chancellor to wear three wigs at the same time, holding pivotal roles in the legislature, executive and the judiciary. The system worked, when it did, only because its holders had an innate understanding of the constitutional conventions. Grayling has no such resources to fall back on. No wonder he has been keeping his own counsel.