A WEEK ago I did not believe that politicians at Holyrood or Westminster would seriously contemplate another March-style, lengthy lockdown.

But increasing alarm over not one, but two, highly contagious variant strains of the new coronavirus circulating in the UK has changed that.

Now I find it difficult to imagine that we are facing anything else as we prepare to enter the new year.

If the experience of South Africa and south-east England is anything to go by, softer circuit break restrictions will not be enough.

We may even need something tougher than we had in March.

A briefing by scientists on the UK’s NERVTAG (New and Emerging Respiratory Virus Threats Advisory Group) noted that the UK variant “has demonstrated exponential growth during a period when national lockdown measures were in place”.

READ MORE: 14% of Covid infections in Scotland linked to UK variant strain

Containing the spread of this strain will require extremely high compliance with stay-at-home rules and self-isolation in particular - something which has been woeful in the UK until now.

In France, anyone leaving their homes during lockdown must complete attestation (‘declaration’) forms stating their reasons for going out - for example, essential work, collecting children from schools, picking up medicines. Residents caught outside without a valid reason or straying further than the permitted kilometre (half a mile) from their property have been hit with €135 (£120) fines.

In Greece, citizens must text their name, address and reason for wishing to leave their house to a five-digit government number to request permission to go out.

This might seem anathema to life in the UK, but can it be a coincidence that in the past few days both Nicola Sturgeon (in relation to stay-at-home guidance) and UK Health Secretary Matt Hancock (with reference to quarantining if you have been to South Africa or in contact with anyone who has) have raised the prospect of legal enforcements for both?

The Herald: Cases of coronavirus have been rising in the south and east of England, where the mutant strain is concentrated, but falling in other regions (ONS Infection survey)Cases of coronavirus have been rising in the south and east of England, where the mutant strain is concentrated, but falling in other regions (ONS Infection survey)

We are in a perilous situation - undoubtedly the worst since the virus first arrived in the UK - and while the prospect of mass vaccination gives us hope, we have a long way to go, at least until mid-2021, before substantial population coverage is likely to be achieved.

If these variants take hold as experts fear they could, we must think seriously about better practical and financial support to enable people to self-isolate, both in the form of of quarantine hotels and making isolation payments either more generous for the low-paid or simply easier to access (in Taiwan citizens are automatically paid a US$33-a-day stipend, but face fines in ranging from $3000-33,000 for violating it).

So what do we know so far about these variants which have cancelled Christmas and look set to overshadow the new year?

The UK variant, known as VUI 202012/01 (as in the first ‘Variant Under Investigation’ in December 2020) is characterised by a total of 29 mutations compared to the original Wuhan cluster - 17 of which appear to have occurred in at once.

READ MORE: We could have had a normal Christmas - but the time to achieve it was July

The leading theory for now - although investigations are ongoing - is that the variant first evolved in September in a patient, possibly in the Kent area, who was sick with the infection for a long time, maximising the opportunity for mutations.

These are naturally ‘copying errors’ which occur at a molecular level as the virus replicates in its human hosts and spreads. Think of it like a 300-page book where every so often a couple of letters randomly switch places as new copies are rushed off the press.

Occasionally one of these mutations will confer a ‘selective advantage’ - such as making a virus more transmissible. As a general rule in virology, however, the more infectious a virus becomes the more its lethality dwindles.

For example, the original 2003 SARS killed around 11 per cent of people who caught it compared to the new SARS-CoV-2 version, which has an estimated case-fatality rate somewhere in the region of 0.1-1% . But SARS also ran out of steam and no case has been detected anywhere in the world since 2004.

A virus’ only goal is to be passed on and multiply, which is better achieved by being highly contagious - but not overly deadly.

It remains to be seen of course whether this will turn out to be the case for the UK variant, which is estimated to be 70% more transmissible and as of mid-December was accounting for around 60% of all new cases in London.

The Herald: The UK and South Africa have experienced a huge surge in cases since the beginning of DecemberThe UK and South Africa have experienced a huge surge in cases since the beginning of December

There has been a suggestion that the variant may be more infectious in children after NERVTAG member Professor Neil Ferguson told journalists that the number of cases of the new variant detected in under-15s is “significantly higher “than other strains, but there is currently no published evidence to demonstrate that.

READ MORE: If only taking back control had applied to our borders in a pandemic

The South African mutation, dubbed 501.YV2, has been detected in two locations in Britain - in London and the north-west of England. It makes up around 90% of the new cases in South Africa, which is currently in the midst of its summer when the disease should have been easier to control.

On Wednesday, South Africa’s Health Minister Dr Zweli Mkhize warned that the “rate of spread is much faster than the first wave and we will surpass the peak of the first wave in the coming days”.

The Herald: In Scotland positive Covid cases have been rising again since early DecemberIn Scotland positive Covid cases have been rising again since early December

Worryingly for the UK, Dr Mkhize has suggested the disease could actually be more lethal in young people, saying that doctors “are seeing a larger proportion of younger patients with no co-morbidities presenting with critical illness”.

However, it is also true that young people may be getting sick because many more of them are getting infected this time around, with students and teenagers blamed for super-spreading the virus with post-exam parties.

The South African variant has more mutations, three of which might affect vaccine efficacy, though this could be rectified if necessary.

In the meantime, standard measures - hand-washing, social distancing, and self-isolation - remain our best defence against transmission. But compliance will be more important than ever.