As we write, Labour is expected to vote for the Government’s proposed new lockdown later today, which will guarantee that it comes into effect.  Conservative MPs unhappy with the plan could respond to this prospect in two different ways.

They could either conclude that today is not the moment to troop through the lobbies against a shutdown, because they don’t have enough votes to stop it happening…

…Or else decide that they should oppose it for exactly that reason: because they will not thereby be inflicting a momentous defeat on the Government they were elected to support.

So to the decision itself.  The best way of starting to make it may be to side-step forecasts – loaded as they are all round with confirmation bias and vested interest on all sides – and instead bear down on the facts.

That’s easier said than done: for example, the NHS in England has changed the way in which deaths are counted at least twice: in April and August.

But the recent trend is clear enough: cases, hospitalisations and deaths have all risen, the last two sharply since last month.

However, the last death figure available in England was 82, compared to a peak of 975 in early April.  That looks like an artificially low figure, but deaths have been declining in recent days from totals of about 200.

The latest hospitalisation figure – to be more precise, that for patients in hospital – was 10,337, compared to a peak of 17,172 in April.

In short, Coronavirus hospitalisation and death figures are well below those recorded last spring.  The Government maintains that the R number is above one, though King’s College London estimates that it is now below it.

But the reproduction and infection rates may matter less than the question of whether the NHS can cope.  And it is crucial to grasp that to compare its situation now with that of the spring is not to compare like with like.

In essence, the service shut up shop earlier this year to much of its usual work – concentrating its energies instead  on what was then a virus new to doctors, nurses and other staff.

It now knows much more than it did, and is attempting both to deal with Covid-19 patients and with all others.  So Boris Johnson is right in principle to suggest that lower numbers could overwhelm the service.

What about in practice?  On this site today, Mark Harper will write that “the published data does not substantiate the Prime Minister’s claim that hospital capacity in the South West would be exceeded in a matter of weeks”.

This site is picking up the same view from other Tory MPs, many of whom sit for rural or suburban seats in which the virus is less prevalent than in some big cities and urban areas (and whose reflexes are thus anti-lockdown).

All in all, Conservative backbenchers should maintain a strong presumption of loyalty – and not only because Boris Johnson won many of them their seats last December.

For with other European countries reeling before the virus, and America on an electoral knife-edge this morning, Britain needs strong government – which would not be consistent with the defeat of its Covid-19 policy.

But, as we have seen, there seems to be no prospect of that.  And against the claims of party loyalty must be set those of common sense, which suggest that the policy isn’t working – and MPs’ duties to constituents.

Ministers are pinning their hopes on a vaccine or new tests, like those being trialled in Liverpool, to get the virus under control and the country back to normal (or close to it).

However, a vaccine may not work to the standard required, or at all; and in any case may be available to only half the population.

New tests that cut out the laborious tracing process, or better results from local tracking teams, may raise the number of those required to self-isolate to the necessary levels.  But they may not.

If so, the strategic choice for Government and Parliament will come down, as Damian Green wrote recently on this site, to either more winter lockdowns or a looser approach for the foreseeable future.

The latter would be roughly that described by Raghib Ali: “one which may cause less overall harm based on the Swedish approach, but with much better protection of the vulnerable, especially in care homes”.

But MPs are not in a good position to weigh the one against the other – since the Government has produced no regular assessments of the total impact of Covid-19, lockdowns and restrictions on lives and livelihoods.

Rishi Sunak recently confirmed that Clare Lombardelli, the Treasury’s Chief Economist, has been asked to undertake an analysis of the economic effects of the crisis.

And the Department of Health produced a healthcare cost-benefit anaylsis of the impacts of the virus during the summer.

So some of the relevant information is knocking around Whitehall.  What’s now needed is for more of it to be commissioned and produced – as we and others are persistently arguing.

It goes almost without saying that no assessment could remove uncertainty from policy-making.  But a series of them might at least start to enable a wider and deeper conversation to begin about the virus.

What, ultimately, is the trade-off between seeking to prevent Covid-19 deaths or seeking to prevent others?  How should lost jobs should be weighed against Coronavirus deaths – or incidences of Long Covid (if at all)?

Where do increases in poverty come in?  How can the value of vanished months of education be best measured, and the consequent damage to young people?  What worth do we ascribe to civil liberties in the balance?

If such questions sound unansweable, it may be worth remembering that government already makes assessments that should make any thoughtful person deeply uncomfortable – through the use of quality-adjusted life years.

They are ones that Ministers and MPs, for obvious reasons, tend to try to avoid addressing.  But such decisions on Covid can’t ultimately be ducked – after all, they’re being made now, if only by default.

We suggest that Conservative backbenchers listen carefully to the brief debate – it lasts for only three hours – and seek assurances that such assessments will be published as soon as possible.

If these aren’t forthcoming, they should withhold support from the Government when the vote comes later.  Perhaps there is no workable alternative to lockdowns, after all.  But until more evidence is available to MPs, it is impossible for them to know – or at least make the better-informed decisions that their constituents deserve.