Faced with the rapidly-spreading omicron variant and the same Sage scientific evidence, the leaders for Wales and England looked at the data and came to vastly different conclusions.
In Wales, Mark Drakeford implemented new strict restrictions for the New Year while Mr Johnson decided to ride it out with his existing plan B measures.
But did Mr Drakeford's strict Covid rules actually make any difference?
Wales' economy minister criticised the "much lower level of protective measures in England" on Sunday. Vaughan Gething might have told the BBC that Wales was right to impose restrictions to deal with Omicron, but the statistics aren't quite as conclusive as he might like us to think.
Yes, the number of daily Covid cases in Wales has been falling rapidly since January 1, from a peak of 2,588 cases per 100,000 population to the current infection rate of just 650 cases per 100,000. Read the latest stats for Wales here.
But there's been a similar drop off in all four UK nations, England included, as shown in the graph below.
England's infection rate peaked a couple of days later than Wales but never got as high and also climbed at a much steadier rate. In effect, despite the restrictions in place in Wales after Christmas, cases continued to rise more rapidly than over the border.
There are two important factors to take into account here. Firstly, England does not count reinfections in its daily case data, whereas Wales does as long as they are more than 42 days apart. Its possible then that this has had a massively distorting effect on the reliability of cases as a comparison between the two nations.
Secondly, the policy on testing changed in Wales and England on January 6. From this date, anyone who has a positive lateral flow test, but does not have symptoms, no longer needs to take a PCR test to confirm they have Covid. This will impact testing figures and therefore daily case numbers in both parts of the UK, although the impact on Wales will be greater as positive LFT figures are not included in the figures here. Thus the decline is likely to appear sharper here because of the testing rules.
Another factor of course is that people may have modified their own behaviour regardless of whether restrictions were in place or not over Christmas. It's hard to forget the sombre face of Professor Chris Whitty telling everyone to "prioritise" what events mattered to them over Christmas. His words may have had more impact that we realise.
It's interesting to note however, that even as UK cases started increasing in December, they were doing so at a much slower rate in England than in Wales. England then, was already seeing omicron spread differently.
When Wales' First Minister announced the Boxing Day restrictions, he did warned the nation that omicron was a fast-moving, high-infectious form of coronavirus while a government spokesperson said: "If this omicron wave infects large numbers of people, it will have knock-on impacts on public services and the economy because of staff absences; it could cause a surge in hospitalisations, at a time when the NHS is already at its busiest, and we could sadly see more deaths."
The overwhelming concern then was protecting the Welsh NHS. So did the restrictions help in that respect?
We can see in the graph below that hospital admissions for Covid, when adjusted for population, have remained highest in England since the very beginning of December. In fact, they've remained lowest in Wales out of all four of the UK home nations all the way through December and into the New Year.
Even so, all four nations have exhibited a similar surge in admissions followed by a plateau and subsequent drop off, despite the different restrictions in place in each. Mr Gething was adamant Wales took the right approach: "If you look at the figures on hospitalisations, and if you look at the gathering data, I'm afraid on mortality, in the last week or so about 1,800 people across the UK lost their lives that's a significant loss of life," he said. "You'll find England is disproportionately a larger part of it. We can be confident that more people would have come to harm without the protections we had in place."
But it's not clear where he is getting his data from. The charts provided by Our World in Data show that when you look at the data on a log scale, which shows rate of change and therefore picks out trends much more clearly, that all four parts of the UK had very similar patterns on deaths, cases and hospitalisations throughout this wave. These figures aren't population adjusted, which is why England appears to have more but the shape of the charts are what's important on a log scale and it is strikingly similar.
There are serious questions for both governments about why they report data differently and why they took different decisions in the face of the same virus and whether they worked.
For Wales the question is whether, given the First Minister's hands were tied by the lack of furlough, it was effective bringing in a compromised set of restrictions.
A clear example of that was the rule banning people from watching sport outdoors but allowing them to sit in a pub and watch it. The absurdity of this was illustrated on Boxing Day when around 140 people were allowed to watch a rugby game in a clubhouse but only 50 could watch outside.
On January 8, data showed Covid rates had risen almost three times faster in Wales when compared to England. Professor Robert Dingwall, a former government Covid advisor, from Nottingham Trent University, told the Daily Telegraph that the omicron variant in Wales was "driving an increase which is not really being contained by these extra restrictions." He believed that omicron is so infectious that "actually nothing you do makes much difference".
If we look at the modelled data for Wales, compared to the reality, we see that it is a much more of a conservative worst case scenario, as shown in the graph below.
There's no doubt that imposing restrictions to protect public health has significant- sometimes devastating- consequences to people's livelihoods, businesses and mental health.
As Wales takes steps to return to level zero in the next two weeks, it's virtually impossible to quantify just how much Mark Drakeford's strict Covid rules changed the course of omicron over the New Year. Mr Gething is adamant though: "I'm generally positive and optimistic that the steps together we've taken over the last month or so have been worth it," he said.
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