TODAY, the Government at Westminster is laying before Parliament an emergency powers Coronavirus Bill. This sounds an obvious, necessary measure to give central and devolved administrations, police, local authorities and medical agencies all the emergency powers they need to cope with the Covid-19 crisis.

However, the extension of police and bureaucratic powers proposed is so sweeping as to pose a potential threat to civil liberties, if used improperly. In addition, these powers are to be granted for two whole years – a timetable suspiciously longer than the 12 weeks that Boris Johnson says is needed “to turn the tide” of the epidemic.

Another case of lefty paranoia? No: more a question of reasonable doubt. For starters, the bill is 329 pages long and the Government plan is to ram it through all its stages in a single day – ostensibly on the grounds it is medically dangerous to congregate all those MPs in the voting lobbies for too long.

Such arguments are lazy, if not deliberately disingenuous. There is no way a bill of this length and sensitivity can be scrutinised successfully in one day. Also, it is perfectly possible to use the present emergency to introduce new methods of remote, electronic debate and voting, that would allow proper legislative scrutiny to take place. Either we are being bamboozled for political ends or important legislation is being bungled. Take your pick.

Even if one subscribes to the “cock-up” theory of government, it is important to remember that British constitutional history is littered with examples of emergency legislation that did more harm than good. In April 1913, the Prisoners (Temporary Discharge for Ill-Health) Bill was rushed through to give the home secretary powers to release suffragettes on the verge of death from hunger strike.

However, sneakily, it also allowed the Government to re-arrest the women after they had recovered – and force-feed them again. Only the intervention of the First World War prevented thousands of protesting women being thus tortured by the state. The is the infamous Cat and Mouse Act, which stayed on the statute books till the 1950s.

Next was the Defence of the Realm Act (DORA) passed on August 8, 1914, barely four days after the outbreak of the First World War. This draconian legislation gave the government wide-ranging powers to ban “false reports” about the war and to intern supposed subversives.

Predictably, the subversives turned out not to be German saboteurs but political protesters against the war and conscription. These included John Maclean and the philosopher and mathematician Bertrand Russell, both of whom were jailed. Incidentally, DORA also gave the Government the right to rule by decree, a provision subsequently used to extend working hours, outlaw strikes and (regulation 40B), for the first time in the UK, ban the sale of cocaine.

DORA was supposed to lapse on the end of hostilities. Instead, in 1920, a new Emergency Powers Act effectively made DORA permanent. Instead of war, an emergency was now defined as any situation, anytime, that the government believed might “deprive the community, or any substantial portion of the community, of the essentials of life ... ” Translation: strikes. The new powers were used extensively to break the General Strike in 1926. They have been used almost continuously against strikers ever since.

The 1920 Emergency Powers Act has been updated from time to time. Its current incarnation is the 2004 Civil Contingencies Act – the work of John Prescott, the Labour grandee who bonked his secretary and got away with it.

The Civil Contingencies Act is the nuclear weapon of state intervention. It allows Government ministers to amend any primary legislation simply by decree, as with the original DORA. Theoretically, Boris Johnson could shut down Holyrood if he thought there was an emergency, say a contested referendum. The one exception they can’t tinker with is the Human Rights Act, you’ll be glad to know. Also, individual ministerial decrees last only for 30 days unless Parliament votes to extend them.

The obvious question arises: why does the Government need extra emergency legislation to deal with Covid-19? Some of the proposed new legislation is innocuous, including allowing recently retired medical staff to return to work in the NHS, with protection given against negligence claims. Clearly it is sensible to put this on a semi-permanent footing, so ministers don’t have to run back to Parliament for extensions, every month.

However, these vital rule changes are combined with unrelated, much broader proposals, granting powers to police or immigration officers to detain people suspected of carrying the virus and “to take them to a suitable place to enable screening and assessment” for an unspecified period. Other measures would allow ministers to ban gatherings or events and (ominously) make it easier for people to be detained in mental hospitals, and for longer periods.

I get suspicious when a government confuses legislating for powers over the person with enacting more innocuous administrative rules for, say, NHS employment. Why propose a huge, portmanteau emergency bill, anyway? Are we hiding something? Or just legislating in a rush, which is equally as dangerous?

There’s another anomaly with the proposed legislation. Curiously, the Government already passed broadly similar regulations on February 10, granting powers to detain those suspected of being infectious – not that many noticed. These regulations utilised the existing Public Health (Control of Disease) Act 1984.

So why add to these sweeping powers? Possible answer: the 1984 legislation applies only to England. The new bill has been prepared in discussions with Holyrood and the other devolved administrations. It formalises the new emergency regulations across all the nations of the UK. As a result, the SNP Government has already announced it will not withhold legislative consent for the bill.

In which case, it is even more troubling that it is being rushed through and that it enshrines such draconian powers for fully two years.

No-one should doubt the scale of the medical crisis we face. But this is a clear attempt to circumvent the (already weak) brakes placed on existing emergency legislation – brakes that force ministers to seek parliamentary approval every 30 days. Instead, ministers (including Scottish ministers), police and Border Force officers will have virtual carte blanche to detain individuals without habeas corpus, order people to disperse, detain citizens in medical and mental institutions, shut events and suspend operations at airports.

Some MPs have cavilled at being asked to rubber stamp such a massive transfer of power to the state – a state run by Boris Johnson, Dominic Cummings, Priti Patel and Michael Gove. The SNP’s Joanna Cherry has already objected. In response, the bill’s supporters point out that it includes provision for the four UK governments to switch on and off the new powers as necessary, based on medical advice. But the point of having built-in democratic safeguards – even if only insisting on parliamentary renewal after six or 12 months – is that you don’t have to rely on ministerial discretion, even Nicola Sturgeon’s. Quis custodiet ipsos custodes?

There is an old saying, attributed (apocryphally) to Thomas Jefferson, that “eternal vigilance is the price of liberty”. We are about to test that injunction to breaking point.