The Conservative immigration spokesman, Damian Green, is not a figure ordinarily likely to elicit much sympathy from me – although Boris Johnson’s call for an amnesty for illegal immigrants was the most sensible suggestion on immigration for many years. But the arrest of Damian Green MP is a constitutional outrage that may finally motivate our supine parliament to stand up to this domineering executive.

When Tony Blair halted the process of law in the BAE corruption case over arms exports to Saudi Arabia, I commented that we had abandoned the principle that no man, however high, is above the law – a principle which we had chopped off Charles I’s head to entrench.

Charles I famously failed to arrest opposition MPs when he arrived at the House of Commons with his soldiers to be defied by the Speaker and find that, as he observed, “The birds have flown”. That attempt was critical in precipitating the country into civil war.

The good citizenry of London and Cambridge will not be grabbing their pikes and muskets today; but they should. The arrest of Damian Green for doing his job of opposing the executive is a step too far in rolling back centuries of democratic achievement. The pretext is the excessive desire of this government to keep all public information secret, and prevent the taxpayer from finding out what has been done in their name and at their expense. This is the most secretive, as well as the most authoritarian, government of the modern era.

I can comment with more authority than most in saying that civil servants now have a duty to leak: the official narrative is now so often far from the truth across the whole field of government, that if civil servants do not leak there can be no informed democratic debate. To arrest an opposition MP for finding out what is really happening is a grim, grim move.