Last autumn, Covid cases, hospitalisations and deaths were lower than during the spring, and an agonising debate was taking place among Conservative MPs.  There were no vaccines.  And faster-spreading variants, such as Delta, hadn’t gained critical mass.

The Government’s tiering plan set colleague against colleague – as each fought for their area to be placed in the lowest tier, and so escape lockdown measures almost altogether.  More began to ask themselves and each other: surely there must be a better way than this?

If the choice was between permanent shutdowns and a salvageable economy, might it not be better to plump for the latter – even at the risk of more deaths than would otherwise be the case?  Read Damian Green’s piece on this site at the time to get a sense of the mood.

Then came the variants, and soaring Covid numbers that took Britain to the top of the international deaths league.  Then, too, came vaccines to bring those numbers back down, earlier than almost anywhere else in the world.  The mood at Westminster changed.

Backbench rebellions, which peaked in December when 53 Tory MPs opposed the tiering plan, subsided.  Neil O’Brien emerged to turn on lockdown opponents the same scrutiny that they applied to others.  Boris Johnson’s score in this site’s Cabinet League table emerged from negative ratings and began to recover.

Later, Matt Hancock, who didn’t care how angry lockdowns made Conservative backbenchers, was forced to resign.  And a Cabinet reshuffle took place which moved Michael Gove, whose restrictive approach to Covid mirrored Hancock’s, away from the decision-making centre.

Hancock was replaced by Sajid Javid, who gave greater stress to the economy (and keeping his backbench colleagues happy: he could scarcely have given less).  The new Health Secretary joined both Johnson and Rishi Sunak in being reflexively hostile to lockdowns.

The Prime Minister himself can’t see the sunny side of a street without crossing to walk down it.  So it proved as the UK led Europe vaccine-wise (so much so that the EU had briefly moved Article 16 of the Northern Ireland Protocol to try keep its own vaccines out of Great Britain).  Johnson communicated an upbeat sense of the worst being over.

This is the background against which to view tomorrow’s vote.  Furthermore, the economy is only just emerging from previous waves of Covid.  The Government is already planning to raise borrowing and taxes.  More restrictions would push the bill even higher, further ravaging the hospitality and leisure sectors.

A few of those backbenchers believe that more deaths are a price worth paying for freedom.  More of them rightly think that the prospect of a population policed by vaccine passports is alarming.  And that the possibility of compulsory vaccination being forced on it is terrifying.

Furthermore, they listen to voices in their seats that don’t get heard in the media.  These are those of people who work with their hands as well as their minds: delivery drivers, shop assistants, factory workers, bar staff without public sector security and pensions.  In short, of a big slice of the “just about managing”.

Such is the background to tomorrow’s vote on the Government’s proposed restrictions.  Those lockdown opponents  are back in the media.  Lists of rebels are being published.  And the measures themselves are easily mocked and lampooned.

For example, they propose that a face covering be worn in a shop that may be empty of other customers, but not in a pub that may be packed with them.  That these be worn while one is speaking, but not if one is singing – at least, when it is “reasonably necessary” to do so.

What happens if a choir fundraising for a charity finds its way into your nearby local supermarket, and breaks into a chorus of “Tis the season to be jolly”?  The Commons’ barrack room lawyers, let alone its real ones, will have a lot of fun tomorrow.

Now stand back from the triumphalist mood since the spring, the inconsistency of the Government’s new plans, and the fragility of Johnson’s standing within his party.  Turn instead to Omicron.  What do we know about it so far, and where does what we know lead?

The cliche about viruses is that they don’t like to kill their hosts; the more they do so, the less they spead – and survive.  These are early days.  But it seems that Omicron fits the stereotype: it is less lethal than some other forms of Covid, but gets about faster than they do.

However, the social impact of Covid is not confined to death figures.  What counts more, certainly in terms of raw politics, is hospitalisation numbers.  The more Omicron cases there are, the more of these there will be – especially given the difficulty of getting a GP appointment, and our tendency to go to A&E in any event.

The Government’s approach to the virus has had its successes and its failures.  One of the under-recognised former is that the hospitals have been spared Lombardy-type scenes of full ambulances parked outside A & E departments, with patients inside the hospitals themselves marooned on trolleys in corridors.

The prospect seems so remote that some are no longer spooked by it.  But the possibility exists.  And what may matter most with Omicron isn’t the proportion of people who fall seriously ill with it, but the number: after all, a small proportion of a big number could be a lot of deaths.

Were they to happen, the recent trend would reverse ferret.  The cry would no longer be: “why are we locking down again?”  Rather, it would become: “why didn’t we lock down sooner?”  And much of public opinion, remember, is still sympathetic to lockdown – especially, it seems, among recently Tory-inclined, older, Red Wall voters.

Such is the landscape that Johnson now sees ahead, and the tensions that he must negotiate tomorrow.  That SAGE advisers are always crying wolf, and that some of the bleakest Covid projections have turned out badly, makes his task no easier.

Maybe the comfort blanket of boosters will prove durable enough.  Perhaps the measures he announced yesterday will be enough to see off Omicron.  Either way, I offer a probability, and a possibility.  The first is that, regardless of the number of rebels tomorrow, Johnson will soon be back, asking for more restrictions as Omicron numbers climb.

The second is that the boosters are not effective enough.  Maybe against Omicron.  Or perhaps against some future variant.  For if much of the world is to remain unvaccinated, it follows that more variants there are likely to be.  Which leaves us and others will the three strategic choices outlined yesterday by Rob Colvile.

The first is to divide the population like sheep and goats in the gospel parable: the vaccinated former would be free to do as they will, more or less; the unvaccinated latter barred from facilities, amenities and services – until or unless they comply.

If that is deemed unacceptable in a free society (as it should be), then the second option is that we all suffer alike – under future lockdowns as future variants, and perhaps Omicron itself, work their way through the population.  The third is to keep the economy open as death numbers climb and hospitals go under.

Or try to.  Would Johnson have the authority to take that course any longer?  Does he have it for any of these three approaches?  I’ve previously compared Covid to a Narnian winter.  But in C.S.Lewis’ book, the thaw eventually comes.  What of Narnian winters that end only to start again, for however long it takes to find new vaccines?