Boris Johnson is using the conventions of British public life to destroy the British constitution. He is relying on the old understanding that good chaps don't 'go too far' while 'going all the way' himself. He is counting on the judges being frightened of challenging him, while showing no fear as he tramps over and tramps down the lines that once marked the separation of powers.

Johnson breaks the rules while insisting that everyone else must obey them. He’s like a criminal who cries with outrage when the police do not follow their procedure to the letter, and the judges should find the courage to treat him as such.

In his message to the Supreme Court, Sir James Eadie QC, the first treasury counsel, said Johnson's decision to suspend Parliament for five weeks was 'high policy' that was no one else's business. The judges had no jurisdiction 'to enforce political conventions', Boris Johnson and Lord Keen of Elie, the advocate-general for Scotland, said in a submission to the Court. These 'matters are determined within the political world'.

Johnson can break conventions, in other words, and the judges cannot stop him. Put like this, the case against his double standards seems obvious. But notice how clever his appeal to the old standards of public life is. We don’t have American judges who act as unelected politicians. Nor I think do most people want them.

Conservative peer Daniel Finkelstein speaks for many when he says in the Times today we are in danger of supplanting democracy with a judgocracy. He quotes with approval former Supreme Court justice Jonathan Sumption, who argued in this year's Reith Lectures that we have always been a parliamentary democracy. The representatives of the people decide. The judges cannot intervene.

Finkelstein didn’t mention it, but Sumption went further. He delivered a bracing attack on the complacent belief that politics can be hollowed out with impunity, and the electorate has no power to limit human rights acts or conventions without the authority of courts of law. In a passage I wanted to refute but had to work hard to find fault with, Sumption said many lawyers believed that a priestly caste of judges should police democratic choice:

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'The essential objection to it is that it is conceptually no different from the claim of communism, fascism, monarchism, Catholicism, Islamism and all the other great isms that have historically claimed a monopoly of legitimate political discourse on the ground that its advocates considered themselves to be obviously right... One can believe that one’s fellow citizens ought to choose liberal values without wanting to impose them.'

Just so. Political arguments should be won at the ballot box and not in the law courts. I look forward with a kind of grim pleasure to seeing the American liberals, who defended interventionist judges when they upheld their values, crying in horror, when the judges Trump appointed attack women’s rights, trade unions and environmental and health protections.

But if the representatives of the people decide, who apart from judges can stop Johnson shutting them out of Westminster? If arguments should be won at the ballot box, by what right does Johnson seek to silence the representatives who won the ballots?

Lord Sumption delivered the Reith lectures in June. Boris Johnson became prime minister in July. In September, Lord Sumption looked at the wreckage his administration had produced and said:

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'The problem is Boris Johnson has taken a hammer and sickle to our political culture, in a way that is profoundly provocative to people who believe there ought to be solutions consistent with our traditions. Undoubtedly the government has behaved disgracefully and that is a situation in which it's going to be very difficult to predict what happens.'

Witness the effect of three months of Johnson on the most conservative of small “c” conservative judges. In the summer, Sumption was urging judicial restraint. By the autumn, he was urging judges to the barricades.

In the Supreme Court, Lord Pannick made the case better than I could. If Johnson was right, everything we thought we knew about the British constitution would have to be torn up, he said. The executive was no longer answerable to Parliament or subservient to Parliament. It had the power to suspend Parliament to avoid scrutiny during a national crisis and the courts had no right to intervene. The judges kept asking Pannick for precedents to guide them. Tellingly there were none because no prime minister has attempted to pull off Johnson’s stunt.

What, he asked the judges, would the courts say if a prime minister ordered the Queen to suspend Parliament for six months or a year and govern as a modern Stuart?

The question was not as rhetorical as it seemed. Dominic Cummings reportedly said the government could suspend parliament for a second time if the Supreme Court found against it. This apparently was a ‘joke’. No one is laughing with Cummings because the Justice Secretary refused to disassociate himself from the gag. For this reason alone, the Supreme Court must assert it has jurisdiction, even if it does not find this prorogation unlawful.

The mass deselection of Tory MPs and the Prime Minister's refusal to provide a witness statement to the court speaks of a governing clique that despises accountability. The old rules bind its opponents but not them. They are the masters now and they are no more answerable to judges than MPs.

As Conservatives are no longer conservative I suppose it is pointless telling them that one day the same tactics could be used against them by a radical left government. The old urges that demanded caution left the party when Vote Leave took it over. Only the judiciary can save them from themselves. But Tories are so lost now they won’t thank the judges for protecting them but rant and whine and appeal for public sympathy as the victims of a ‘politicised’ judiciary that is out of control.